I looked at the pictures you have posted here, now, and i see absolutely no apparent evidence of mbd. Absolutely none. He looks a little thin, but males are leaner and not as round as females.
You know, he looks the picture of health to me. I, prsonally, like my boys to have a muscular look about their back legs and tails. I think that thicker, bigger look comes w age.
I am not as experienced as some of the people on here and i am awed by their accumulation of knowledge, but i know what i know, so i will pass it on to you.
If i offer food too much, they become picky.
I have noticed that each one has a preference for when they like to eat.
So, if it were me, i would definitely do that every other week calcium with d and then on the opposite weeks I would give him vitamins. I would put some calcium without d in a shaker and sprinkle calcium without d every time i fed him. I only put it on the first three or four crickets and after that I don't give him any more that day.
I also would feed him his meat first and after he has eaten the amount that is customary (whatever that is) I would offer favorites. That way he is encouraged to eat more.
Im assuming, lights, temps, habitat and air quality are correct.If you dont know, let me know and Ill tell you mine.
I do a lot of individual adjustments. Different chams like different stuff so I tailor my husbandry to fit my guy.
Again i dont know nearly what these other guys know but i have cared for distressed animals and brought them around to good several times