Pre emergent advice

I just recently built a house on 2 acres of land that was mostly St. Augustine with some carpet grass and Bahia before located in South LA.
We brought in top soil to spread thin over the entire 2 acres to level the yard in hopes that the St. Augustine would pop up through. Well we did this back in May and since then, it didn’t rain for 2 months so only about 50% popped through. The other 50% pretty much got over run by barnyard grass mostly and some goose and crab grass. During the winter, we have a lot of clover and chickweeds also from past experiences.

Anyway, I’m trying to come up with a schedule for pre and post emergents and here is what I’ve gathered based on other posts in this group and I’m looking fire advice and critiques. I just spot treated most of my yard with tenacity just to slow the spread and seeds from the barnyard grass.

Mid February & early October: spray Prodiamine (1/2 annual rate) + MSM turf. 6 weeks after that, spray simazine (1/2 annual rate).

For Post emergent: I still have some tenacity left and possibly mix that with MSM turf and spot treat as needed. I know a lot of people recommend Celsius but I don’t want to damage the carpet grass just yet as grass is better than weeds atm.

Any advice is appreciated, but my questions are: is that a good time to put down those products? Do I need to do the split application? Should I mix a sedge product with one of the pre emergents?

I’ve also dabbled with the idea of getting my applicators license to have access to Atrazine and even other insecticide chemicals - does anyone have any experience with this and do they find it as worth while? I didn’t see any posts on this forum related to it so it’d be nice have those people share their inputs.