I would definitely recommend Paradise over Alexander (but, I am not a fan of Alexander). There’s a pretty good map of the OW-friendly springs
here.
My favorites for open water, in order (and I’m out at the springs 2-3x/week):
1. Buford (most fav)
2. Ginnie
3. Paradise
4. Devil’s Den
5. Orange Grove
6. Catfish Hotel/Manatee
7. Blue Grotto
8. Royal
9. Rainbow River
10. Troy
11. Fanning
12. Alexander (least fav)
Avoid Ginnie on the weekend, and go early during the week. I prefer the state parks for weekend diving; DD, BG, & Paradise have much better vis during the week when classes aren’t around and there are fewer divers in the water. If you go to Buford, you need to get a permit first (easy, it’s all automated online) and bring a cart. If you do Rainbow River during the week, call ahead to make sure the water taxi is available. Paradise is closed on Mon & Tues. Otherwise, no reservations required.
If you’re in the High Springs area, Cave Country & Extreme Exposure do quick generous air/nitrox fills. Check out Amigos if you have some time to kill and tanks that need filled - it’s an experience! Devil’s Den and Blue Grotto do fills on site (but are more expensive).
I see in your itinerary you plan to do DD & BG on the same day - that’s a great plan. I’d do BG first (much deeper, DD bottoms out around 50’). Devil’s Den, Blue Grotto, and Ginnie all have hot showers - much appreciated after several days of cool water! Bring soap & shampoo and you won’t have to shower again in the evening.
Most of all, have fun! I love the springs - and bring that camera, esp at Ginnie. I’m also mostly macro but the gin-clear water makes for awesome wide-angle shots.