[pierrot]

If this were my concern I would take the new booster back to the parts store, show them the problem and ask that they straighten the master cylinder mounting studs on it. If you do that adjustment and damage the studs in some way then the booster will not be returnable. Candidly, I suspect that you will probably not damage the booster yourself if you are cautious. However, the point here is that one should to consider possible consequences if something goes awry. I hope that all goes well with the repair and it can be completed soon!