I ran into the same problem with the thighs, but found that rather than scale up the entire piece, I could just modify the pep a little bit. First, I cut out the "ridged" section on the interior and replaced it with vinyl that was cut to fit my legs. This helped lower the profile a little so I could stand relatively normally. Second, I expanded the bottom ridge piece of the pep by freehanding some cardstock pieces. It worked to accommodate my legs, so the height stayed the same but with more width.
The velcro will probably have to be sitched in place to get it to stay, unfortunately. The only real alternative is a harness system to hold it all up, which requires even more sewing but does hold pieces pretty tightly in place.
I still haven't gotten my boots to work yet so I'm afraid I'll be of no help there, but hopefully you can work the issue out and enjoy the suit you've worked so hard on!
The velcro will probably have to be sitched in place to get it to stay, unfortunately. The only real alternative is a harness system to hold it all up, which requires even more sewing but does hold pieces pretty tightly in place.
I still haven't gotten my boots to work yet so I'm afraid I'll be of no help there, but hopefully you can work the issue out and enjoy the suit you've worked so hard on!