Well a good beginning size in my book would be around 7-9". This is the case with most of these around three months of age. At this point they will probably be eating 1/4" crickets, 15-20 a day. At this point I would supplement calcium/D3 everyday. A multivitamin every two weeks. Why, everyday? They are extremely fast growers and 1/4" crickets in my opinion do not gut load signifigant enough. Crickets, maybe a freshly shed mealworm, moths, small silkworms are all they can really handle or at least all I have attempted to feed at these small sizes.
After a month to two most will be able to handle 1/2" crickets. The amount of crickets will drop to the 10-15 range. At this point I would cut back to every other day. They can start eating stuff like super worms and larger silk worms. The reason I like superworms and silkworms: they gut load well (more direct at supers), have close to even C

levels to begin with, full of moisture (some stuggle to keep veiled properly hydrated), they are easily obtainable with supers or can be hatched out controlled with silks. I still supplement multis every two weeks.
Once they move up to 3/4"-adult crickets males can set into their adult type supplementation schedule of once a week with calcium/D3 and females I do at once every four days. I would wing this down not just a drastic cut. Multivitamins for both I do once a month. I have went back to once every two weeks in times of crappier feeder food. Get stuff form work for free.
Males and females usually reach the maximum size they are going to get around 12-15 months. The amount you feed them will drop of dramatically. I feed my male 6 crickets (or equivilant feeder amounts) every other day, the female 4 every other day. Diet has to be watch with both females more then males. To much food for females usually means large clutches. To much for males they will become a little lethargic and obese. When they are growing it is hard to tell if they are fat, usually so active it would be hard for them to be anyway. When full grown it is easily spotted by a bulging casque and chubby cheeks. You can kind gauge what to do then.