I just read that like 3 times and still am not fully sure what is going on.
Are you worried about how big your boots will be in relation to the size of you foot without boots on and if this will cause problems with your board?
If you are a size 10 foot then most of the time you will go down a boot size for snowboarding.
If the latter is correct then you should have no problem with waist width on a new board with size 10 boots or smaller.
Also at 120lbs 157 might be a touch long for some, but just check the weight specs of the board and know what you will be riding with it which can influence board length selection.
Last edited by Smokehaus; 02-17-2011 at 12:29 PM.