I went to your thread and saw your primer was pretty dark. That will probably dictate how much paint it's going to take. Looking at photo's and staring at it from 12'' make's a big difference. I still have not posted picture's of my bottom
I ordered 1 kit (wasn't enough) I ended up using 2 quart kits (1 gal total material) of Interlux VC Performance Epoxy (4 coats). I only had to use a small white foam roller with no tipping necessary. It took both kits to where you could no longer see my primer (system 3 primer, a lighter grey than yours)
That's some nice stuff.