Another option is to have conical locknuts on the hub like Shimano did when 130mm was first produced. The conical shape the locknuts help spread out the frame as you pull the wheel in. I used this on all my 126mm road bikes for over a decade of racing without any problems. I did break 2 aluminium and 3 steel frames during that time, but that was from crashes and major abuse. Spreading the stays didn't cause any issues.