I thought I might have an answer or two, but you really need the expertise of gardengal. She's from your area and can be much more helpful. I expect she will find this and help you out.

Too bad there hasn't been much interest in your question, but the topic does interest me, so I'll add my experience.

Turf grasses have been doing poorly for me in the Willamette Valley. Our lawn started out as sod, probably perennial rye (with embedded plastic grid, which I abhor). Our dogs really tear up the weak turf, running and playing, and the orange clay soil makes a real mess in the house. I purchased "Northern Ecology Lawn Mix" from Nichols Garden Nursery and over-seeded our dreadful lawn in spring of 2022. The mix contained some clovers but I don't think micro-clover (Trifolium repens var. Pipolina) was one of them. I don't remembering them offering micro-clover then, but I may be wrong, they do have it on their website now though. The clovers in the mix I used have done very well, love them! The English Daisies in the mix have done spectacularly, and I would highly recommend. They bloom all winter here, and I'm not being hyperbolic. They have been blooming non-stop since September, and will continue through April, at least, depending on when the heat arrives. It goes without saying, since they bloom all winter, that the English Daisies are also fully evergreen.

I highly recommend trying the micro-clover, I might order some from Nichols Garden myself. I would not recommend the mix I used, it was 95% grass, and the grass did not take. I would buy all clover seed and add English Daisy seed as well.

I didn't remove any grass sod before seeding, but our lawn was very spotty and patches of bare soil were abundant. I just mixed my seed with potting soil/compost and packed it in to all of the dead spots/bare soil patches.

I'm also going to try Isotoma and Pratia (are these two genera really any different from each other?) this spring.

Good luck!

@artinnature Thank you! I actually found some good advice over at Reddit r/NoLawns. I plan to purchase this brand, recommended by a guy in Seattle who has had very good results with it.

Our lawn was very old and hard packed. I just got it tilled really well so it's ready for seeding! I'll probably do it mid march.

One question-- since our lawn was tilled, how should I plant the seeds? I imagine it will get slightly compacted again over the next couple of weeks, so I plan to rake those areas to fluff the dirt back up again and then scattering the seeds. But should I do anything else? Like try to tamp the dirt down after seeding?

The tilling (and/or fluffing) was unnecessary and actually somewhat counterproductive. You have likely dislodged a whole bunch of weed seeds that will now germinate. And have also produced a bumpy, lumpy surface that will settle unevenly. Somewhat less of concern with what you are attempting but really bad news if seeding a turf grass.

Roll or tamp firmly to even out and settle the soil. And seed as soon as possible. I have no idea what sort of seed blend is suggested in reddit (which I avoid) but artinnature's suggestion to not limit your seeding to just clover is a smart one. My "lawn" is completely untended by intent and is a mix of turf grass, moss, English daisies, several species of clover, speedwell, creeping Charlie, beach strawberry and some random bulbs most likely planted by squirrels. I never water or fertilize and it remains green year round and even now is flowering.

I would strongly suggest some periodic watering this summer but you should be good to go after that.

The tilling (and/or fluffing) was unnecessary

we did need tilling in our case. the yard was bumpy, and nearly 1/2 of the area was covered in old walking paths, pavers, and a spot where mud practically turned into concrete. our guy tilled deeply and raked it smooth. it's so much flatter than it was before. we made the choice to let the ground up old grass become mulch.

this yard is tiny, so I'll pull dandelions as they come up. there were some other kinds of tiny, low growing yellow flowers and a big patch of white clover. if those come back mixed in with the old grass and new miniclover, I think it will be fine. if I'm unhappy with the outcome, I'll mix in other species. I do love english daisy!

this is the brand we bought, I chose it based off a recommendation from reddit. that guy lives in the same city as me and has had really good results for a couple of years with low maintenance (no watering), so I felt like that was my best bet.

We did need tilling in our case

No, you did not. If it was uneven then you need to level it, not rototill. It may seem level to you after tilling, because leveling can be approximated, but the soil is almost certain to become bumpy again beginning immediately. The problem with hand held rototillers is the operator cannot control the depth continually across the entire area. When a tiller hits a wet or soft spot, it digs in deep before the operator can pull it up. When it hits a root, rock, pipe, concrete, or dry spot, the tiller bucks up out of the ground and leaves a high spot under the surface. Thus there will be a rolling profile under the fluffed up soil on top. When you drag a drag over the surface to level it, the end result will be 6 inches of fluffy soil here and 4 inches of fluffy soil there. When it settles, the 6 inches settles more than the 4 inches leaving a hole at the surface. This is in addition to the issues raised by GardenGal48.

The leveling process, without tilling first, leaves the soil intact and fills only the low spots with soil or sand. The underlying soil is already settled and the structure is established. By adding sand on top, only the surface addition needs to settle. Once the roots and grass stabilize at the surface, the sand firms up and you notice a much improved surface profile.

it's already done, but thanks for your input anyway. 🤷