Default place to wish for GMs is the Barbarian's glade, though I've seen crazy people wish for one while clearing a greater undead vault and come out on top.
GMs in wilderness will still yield an easy multiple-hundreds-of-thousands exp a pop. With the number they are generated in, it's a guaranteed Lvl 45 if not closer to 50.
Lastly, GM wish is just as risk free as AKW wish. Unless you do something dumb, you won't get hit once (and even if you do, it's unlikely you'll die unless you are very frail).
gate closers: GeWi GnMo(unarmed) DeAs/Pa/Mi(staves)/Ra GePr DrBb HrMo | p7: MeBf | p17: GnPr | p20: DrDu GnAs DeCk MeWp OrBf GnTh MeHe | R57: MeDu | R101: DrAs (26,674 turns) GnDu (26,748) DrAs (18,533)
ULE: HeRa — OCG: DeMi
currently speedrunning DrAs.