Yeah, basically, I didn't use a drill bit, at first I used a piece of emery paper wrapped around a drill bit, but when I realized I needed a bit more metal removed, I used a stone in a die grinder and just carefully clearanced it a bit.. then finished up with emery..
Shouldn't have had to do it, but it was faster than waiting for a replacement extension that may or may not have been any better..
It was the extensions that varied, one would fit right on both struts, and the other extention, the other wouldn't fit anything.