Tulips are true bulbs and multiply by producing offsets, whereas Crocus are corms and the old corm dies each year and a new one develops on top of it. As the corm becomes larger, more flowering stems are produced, similar to Cyclamen.
The species Tulips can produce large colonies from a single bulb, but if left undivided for several years, the flowers will become smaller each year. If you lift and divide them periodically, spacing much closer than 12" is feasible.
They require good drainage and alkaline soil to perform best. You will probably have to dig deeper than the bulb setting depth and ammend the soil with a porous material, such as composted ground bark, for drainage and to allow for root development. If your soil is acidic, incorporation of Lime (5 lbs per 100 ft.²), along with 5-10-10 or 6-12-12 fertilizer into the soil would enhance performance.
Unfortunately, Tulips are very attractive to squirrels, which will dig and eat or store them. Treating the bulbs with Ropel before planting helps, or use a fertilizer that incorporates Coyote urine as a repellent. I cover my bulb plantings(except Daffodils, which squirrels don't bother), with a 1" wire mesh(chicken wire), until the soil settles after a few periods of rainfall or until the bulb foliage dies down in early summer. Once the soil is compacted over the bulbs, the squirrels lose interest in them.
I've not planted Tulips in my lawn, only a few thousand Crocus and Iris reticulata. Using a bulb auger and cordless drills, makes short work of an otherwise tedious and backbreaking job. :Good luck!
Rb

Little Beauty and other small botanical tulips can be planted 3 to 4 inches deep and 2 inches apart. We rarely plant even the larger hybrids more than 4 inches apart.

One issue with small bulbs (because of shallower planting) is they can be detected and dug up by squirrels. We sprinkle blood meal over shallow planted bulbs and this deters the squirrels.

Note: you can use a cheap 1.5 inch regular wood bit (99 cents) to drill a hole to plant small bulbs in the lawn. We drill the hole, put the drill in reverse to remove the soil... drop a bit of good soil into the hole...drop in the bulb and add more soil. Takes a few seconds for each bulb and there's no marks on the lawn after a couple of days. For larger bulbs such as daffodils, hybrid tulips, etc. you need to dig a hole or use a bulb auger.

Rb and Alpiner,
I appreciate all the info you both gave me! I have some Ropel left, but will probably have to buy some more....think maybe my local nursery sells it. I also have lilies coming. October is usually such a busy month for me...planting, cleaning up beds, getting roses ready for winter! I think my husband will love the idea of using his cordless drill! LOL Thanks again, guys! :0) Phyl