The idea with cool weather grass is to help them get through the stress of the hot summer, which they do not like. To do this you feed it in the fall and winter before ground freeze, and once again in late spring (around now for fast acting inorganic, early may for organics). It is like an athlete carbing up the day before a competition. You need to eat in advance of the competition, not during. Likewise with your lawn. You don't want to feed it in 90 degree weather and force it to grow when it would just as soon take a nap and save its energy. For that reason I'd say skip anything that releases nitrogen during the hottest months. This might also encourage fungal attack under the right conditions. Just get the cheapest brand (usually Lesco) of high nitrogen, low everything else fertilizer. Sometimes you can find 50-0-0 or 42-0-0, something like that. As long as the first number is a lot bigger than the other two, you're fine. Follow the directions, and consider going organic, at least for part of the year, but that's another discussion.

Oh my!! You are waaaaay overthinking this. We're going to save you a lot of time starting with mishmosh's info about KBG spreading by itself. You can dispense with overseeding from now on. Overseeding is a fescue and rye grass thing, not a KBG thing. The only reason to overseed KBG is to bring in some different cultivars which might be more cold tolerant, disease tolerant, more heat tolerant, or have a deeper green color. But once you have it down, it will take over. So now you have your fall back. Oh and don't top dress with soil unless you have low spots that fill with water when it rains. The soil you have is fine. If you don't think it's fine, we can help you with that, but don't get into the top dressing habit. I've seen lawns raised 10 inches above the designed level from 40 years of topdressing. Wanna see some pictures? KBG is one of the sod-forming type grasses that spreads by itself without any need for overseeding. If it becomes thin for some reason, assuming it is in relatively full sunlight, it will refill the thin areas without ever overseeding. Spring is not the time you want grass seed to germinate. If you were to seed in the early fall, which is what is recommended for cool season grasses, then water it lightly 3x per day, it would germinate in 3 weeks. That's all there is. When grass germinates in the spring, the tender roots often die in the summer heat. You ran into the other reason for not seeding in the spring - weed pressure. You don't have crabgrass and other summer annual weeds germinating in the fall. There is a rule about KBG and many other ground covers. The first year it sleeps, the second year it creeps, the third year it leaps. Just be patient and you will be rewarded. mishmosh mentioned deep and infrequent watering. What that means is one inch of water all at one time. Then don't water again until the lawn needs it. Put some tuna or cat food cans in the yard and turn on the sprinklers. Time how long it takes to fill all the cans. My oscillator sprinkler takes 8 hours on a full sweep. Your sprinklers likely will go much faster, but I like a long, slow soak. If you get runoff before filling the cans, stop watering and stop the clock. Give the water 15 to 30 minutes to soak in and resume watering (and the clock). The runoff problem will eventually go away. Remember the time it takes to fill all the cans, because that will be your watering time from now on. In the hottest heat of summer you should water about once a week. As it cools off change that to once every 2 weeks, 3 weeks, and then monthly for the cool months until about April. This coming Labor Day you can put down some fertilizer. I use organic fertilizer all the time, but if you want to use chem I'm not going to fight about it. I would suggest using an organic at least once a year to keep your soil in good health. I believe the KBG folks like to fertilize 3 times in the fall. The last one is the most important one for next year. They wait until the grass stops growing but is still green. Then they use a fast acting, high N, fertilizer like urea. The idea is to force feed the roots but not force the plant to grow. The new growth would be susceptible to freeze, so wait until it is no longer growing. Then in the spring you do NOT have to fertilize again until Memorial Day. The only thing to do in the spring is early preemergent herbicide. Apply when you first see forsythia blooming in your neighborhood. Then in April you can spot spray any broadleaf weeds with Weed-b-Gon or Weed-b-Gon Chickweed, Clover, and Oxalis Killer. That should do it for chemicals. Put the RoundUp away. If you think you need it, please ask here first. There are plenty of alternatives for specific issues. Always mulch mow at the mower's highest setting. I would not reseed, dethatch, aerate, or topdress. If you are doing everything right, you should never need to do any of that. All you have to do is water, mow, and fertilize for the rest of the year. This plan should save you a lot of time and money over what you were planning. Here are a couple of motivational pictures. First is a bunch of KBG lawns. Thanks for morpheuspa for posting this summertime picture several years ago. The main difference between the green one and the rest is the green one was watered once a week while the rest were watered daily. Morph uses only organic fertilizer, by the way. This next picture shows the effectiveness of organic fertilizer.The green spot was caused by alfalfa pellets. They were applied to this zoysia lawn in mid May and the picture was taken in mid June. It takes about 3 weeks for organic fertilizers to work, but they clearly do work. Thanks to mrmumbles for posting this.

It looks fantastic!

Thank you mishmosh. I have started doing the same thing and appreciate your comments. I have not transplanted any KBG yet, but plan on doing that as well as time goes by. I use a zero turn mower and with my best attempts, I occasionally get a divot in the lawn. Frustrating, but seems to be a fact of life with a zero turn mower. Life would be easier if lawns were always at the appropriate dryness for mowing. I know, one wheel moving backward and the other moving forward. Sounds easy but I still get the occasional oooops. Suggestions for this issue would also be appreciated by some of the expert mower operators. :-)