order a size down from your jeans. I'm pretty sure thats right. and it should be fine if ur ordering the new sprawls, because they give or take a few inches with their new system. HCK, u can be a little off in size, because they have little elastic parts on the sides which will stretch with added weight.
Sprawl -
www.sprawl.tv
HCK -
www.howardliu.com
~Foz