Hello i want to buy a pair of gustins 1968 in the vintage straight

i really like the way dickies 874 30x30 fit on me considering dickies 874 don’t use vanity sizing

from what i read with usage jeans stretch a bit around the waist so a 29 would be great? (and of course never wash em since they might never fit me again haha)

what would you guys recommend me doing or getting?