I like to keep track of lots of things, or I become bored.
Here are my changes.
1) XP for magic items the player characters find. 100 xp for the item, 250 gp if the characters sell it. Artifacts don’t get XP.
2) No training in B/X. I think 1 day of training, 50 gp, will work fine.
3) Just like the rest of this game world, no level limits. Crestar is not humanocentric. Nor is it a parallel Earth nor resembling Amber.