Guys, I've been using Dave's mounts all the way up through the 180.
As blw has suggested I use the internal hex available through DuBro-----zero problems.

Because I wanted lower and lower noise levels I switched to some Hyde mounts which Merle was good enough to make up for me.

As I look back on my concern (years back) about whether or not the mount would be strong enough I have to laugh at those concerns-----------it will be around with the cockroaches ----- if you get my drift?