i have not read the whole post, but agree with Ric, pennscola bahia will be a PITA to mow the seed heads will bend over and pop back up. argentina would be and has been my choice. yes it's $$. check into a slit seeder rental and google agrentina seed germination.
the seed MUST be in contact with the soil, but if to deep you will have less than disireable results. also check with your county/town for water restrictions, well or city you still must comply. and alot of municiplaties have NO provision for seed, just sod and plugs. one of my cust got a 500.00 fine last year. remember when you water you just need to water to the depth of the seed, any heavier would be a waste and poss wash some away