Guess you're not getting any answer because nobody makes their own, or rather consider it too much of a hassle and just approximately measure bulk-powders with a spoon. As I usually do.
ChuckArbogast wrote:What is the best quality empty pills?
How do you determine how much can go into each size of empty pill? Is it different for type of supplement?
What is the best device to make the pills with?
Are there any other items that I would need to get to make the pills, other than pills and the device?
Empty capsules are either gelatine or a vegan kind. Choose what you like.
Easiest to determine how many Mgs go into a capsule is ether with a Mcg scale, or by weighting the powder filled divided through the number of capsules. Each powder has an unique specific weight, and the same capsule sizes will contain different amounts.
Only know the small manual capsule fillers. Which are straightforward for small amounts of capsules filled, like for a vacation. Guess an industrial capsule filler would cost quite a lot. Only need empty capsules, the filler machine, bulk-powders and empty supplement bottles to package them.