I wanted to try the '42 jeans out because they're a bit unique, no one else is really making repros of this model that was made for a short period of time.
I also felt like I washed my WWII pair too often, so I want to get a little more contrast this time around with the same denim to see how it fairs.
@mstax the 601xx '51 jeans / 507xx are perennial releases as far as I know, so you should be able to get that tux setup more readily than the seasonal releases.
No experience with boiling jeans that hot, but I'd avoid it due to the prospect of possibly ruining the patch.
I've always found that a hot wash with normal agitation from the washing machine gets the most shrink, at least with our washer setup.
Temperature is only one factor in shrinkage, agitation is equally as important in my experience.