I bought a set for some 15x12 steel wheels I have. $300 for snow wheels is a lot better than the cheapest beadlock option (almost $1200 ) I think they will be just find in the snow.
That's for the info. By the looks of the rig, you weren't using them exclusively in snow?
I think you made a good choice going grade 8. My current wheels used 18 5/16" bolts, I grabbed a bag of grade 5 bolt from my work for cheap. After a few months I started breaking a lot of bolts. Didn't seem to be related to what or how I was driving, I'd just randomly noticed broken bolts.
I figured if I was going to replace them all I mine as well step up to 3/8". No issues since with grade 8 3/8".