You're probably 10-20 mins away from me. I did roughly 15k square feet of bermuda by seed the last couple of years. I'm in no way an expert but have definitely picked up on a few things. Seed I got was from Hancock Seed; always germinated nicely for me and the customer service has been good. You basically need to water the mess out of it to get it to fill in quickly. I was watering roughly 3x a day the first couple of weeks and then slowly dialed it back. I would recommend also skipping the fall pre-emergent.
Some areas didn't fill in great the first year or so. A lot of this was due to what was under the dirt - rocks, builder debris, etc. I have a lot of hot spots in my front yard I still need to do the screw driver test on and see what might be there. It's never ending how much crap a builder leaves and grades over. I partially blame myself. This year I have focused on spoon feeding my back yard (area I mostly care about) with high nitrogen every couple of weeks and carbon products in between. Beyond that, I committed to mowing low and often all summer. It's really come in thicker this year. So moral of the story is that it may be sparse your first year or so, but no need to worry.
My current issue is all of the KR Bluestem weeds I need to eradicate, but that's gonna be a tough one. I still haven't found a pre-emergent that's been super effective for me, but was able to find someone selling off part of their Rezilon, so will give that a try the next few applications.