MOTM

I've got a few Blacet built frak modules that I want to mount to MOTM 
panels w/ stooge brackets.
Some of the PCBs have mounting holes  - so that's pretty straight 
forward.

A couple don't have holes and are rather tightly packed.
I'm trying to avoid drilling through the PCB , so I'm wondering whether 
anyone has ideas about other mounting methods.

Thx,

john