I think most folks underestimate how much Momotaros shrink. I'd say BIG's estimate of 2 inches is more accurate. And while they will stretch back an inch at the waist, the rest of the jean (i.e. thighs) wont stretch back that much (if at all).
If you are a guy with skinny thighs and butt, you might be able to get away with the 32s (thought I'd put them on before they completely dry from the presoak, in case you need a little stretch around the waist). On the other hand, if you have fuller thighs and butt, get the 33s.
The unsanforized models (Vintage Label) do not shrink that much. One inch is accurate (Waist... Inseams shrinks two inches, give or take). Only the shrinkage is hard to counter, because of the denim being so tightly woven that it is hard to stretch.
This statement is based upon my own experience, by the way.