As a rawhead I ask myself what the negative aspects of the one washed ones are?
with one wash, u can wear them without soaking them first
i dont think its recommended not to wash ur jeans for 1year.. u can get a massive crotch blowout if im not mistaken.. but its ur jeans, ur rules :D
eniwei for ur sizing.. maybe u can check 1 page back.. i posted a photo there comparing my true size (31) and my down size (30).. if ur looking for relax fit, i suggest taking ur true size.. but the waist will stretch quite a bit
hope this helps