I use the Reptivite with D3. I couldn't find too many choices out there when I was looking. This stuff lasts a long time 'cause I only have the one critter to care for, so it'll be a while until I need to find something different. Still doing research to see what's out there .
I use it for my veiled twice a month (as long as I remember what week we are in!) I try to use it on the first and third weekend of the month, and skip the fifth weekend when that happens in a month. This keeps me on schedule (sort of ) I do dust with the non-D3 daily, but this routine is for a veiled! Not sure for Bowser, but someone should be along soon with advice. Its just like everything chameleon... be patient . He He....
Plain Calcium (no D3) everyday. Calcium with D3 twice a month.
Mutivit once or twice a month. Same for panthers and veileds.
Schedule varies depending on D3 levels in powder (different brands).
With this selection - Calci Dust for daily. Reptivite or Nutrobal twice a month. Exo terra (my brand! lol) is multi vit of course.
How much? A light dusting for each insect every day. Just a little sprinkle of multivit is all I give, on about half the days insects.
Lastly - lots of people will give less D3 if their cham gets a lot of natural unfiltered sunlight.