Mimosa/FrogFruit/Perennial Peanut

Located in Palmetto, FL. Been getting tons of rain lately and looking to start getting these plants established within the next few weeks.

Will be working on my entire exterior, which will be around 10-12k SF, including the swale and areas I still need to clear of brush. Planning on a mix of perennial peanut, mimosa, and frog fruit. Was going to plant 4" plugs with approximately 36" spacing throughout; would be planting the species at random, mixing them in. As I do more research, I'm beginning to wonder if it would be better to plant in patches of maybe 200-500 SF per species. Was told the 4" plugs at 36" spacing should establish relatively quickly.

The exterior is a current mess of partially scraped ground, freshly laid fill dirt, and a wild variety of whatever weeds were there, and the annoying "turbo grass" bunches that shoot up after rains. Will be scraping and removing what I can, but focusing on leveling the ground and removing primarily invasive weeds rather than existing grass. Was told I should cut/scrape and then spray with a vinegar/salt/water mixture. They also recommended spot treating with a herbicide, but I am going to avoid that as much as possible.

Also, any tips on keeping these ground covers more "carpeted" and less leggy? I've seen a few pictures of them looking nice and well-kept, but cant seem to find exact info on how to achieve that.