Some say the sj crank having a smaller sludge trap hole has more potential for over grinding than the relatively thin walled lj crank but I have no experience to back that theory up
I've heard certain triumph con rods can be fitted to sj cranks and provide more regrinds so maybe you should keep this topic alive snd wait to see if anyone can post on this before givIng up?
My bikes big ends are newly ground to -040 and I also have a spare crank already on '040 and needing a regrind so I interested to know if the spare is just a paper weight!