Supplementing at every feeding might be a little much?? The fat soluble vitamins can build up in their systems.
I use Miner-All, but only for babies and only every 2nd to 3rd meal. I just dip the pinkys butt in it and shake off the excess. Pinkys have very little calcium in them (undeveloped bones).
I also use it for my breeding females, but only during the breeding season. I'm not sure if it helps or not, but it makes me feel better. I know it (Miner-All) made a big difference with my leopard geckos during breeding season (better looking eggs). Once again, I only use it every 3rd feeding for the females.
The best way to tell, would be keep some on the supplements and some off. Feed them all the same meals, and see if they live longer, are healthier, etc.
Just my opinion,
Brian Miller