Quick question about fitting correctly.

Questions about fitting correctly. I prefer pull ups in general due to a couple things. Diapers always get loose and leak but pull ups do to but not as fast. I know my body is weird shaped. I used to be over 300lbs and now I am 215. I still have a little bit of a belly and no butt. everything wants to roll down or slide down. I wear compression shorts over them and have tried body suits. I was wearing a medium in live dry ultimate now I buy large. I am very active and walk on average 15 miles a day. I am not opposed to wearing a tape on diaper due to lasting longer and possibly not having to change at work. Any ideas. Thanks everyone.