Hey guys, here update with the boots piece design for Shazam costume!
I 3d modeled the sections and pieces separately so make it easy to hook up the boot of your choice & sizes, there is a back seam leaving it open gap cater for easier accessing the back zippers.

Of course the pieces could be mold and cast in rubber piece to fit even better in profile, general thickness in 2.5mm and sole length at 30cm but remember to take some measurement offset like 2-3cm for the actual foot size. Anyway if you have question about this may just shot me pm I will be happy to help out here. Cheers!