The thick gauge to prevent voltage drop is needed over the distance.
No harm in stepping down, via a dulal-post buss, asymmetric butt connector, ferrule, whatever.
If you just trim strands, be sure to seal the end well against corrosion, even if tinned type wire.
The biggest issue was working out if I’d have to cut too many of the strands. I decided to step down to #6 just before the socket and use a splice kit instead. Other end will also be a #6 wire as it’ll only be a foot or so long. Saves me having to modify the socket to accommodate the sleeve too.
Witts End has some SB50 and SB175 mounting brackets.
Wits' End, Solutions for Problems You Didn't Know You Had
Wits' End, Land Cruiser, 80 Series, LX450, 100 Series, Fire Extinguisher Mountabsolute-wits-end.com
Thanks. Went with the one I linked to, but I’ll keep this in mind if that doesn’t work for some reason.