Mike,
I personally would have to see some good evidence from others that this wouldn't' cause any harm over the long term. My experience with pushrod tubes on previous airplanes is that they can be pretty delicate, easily dented (around spark plugs, by careless mechanics), and can fatigue to produce leaks. Maybe none of this will happen if you attach a brace, but if it does, you have ruined a tube (at best). But....you can easily attach the brace to a bolt on the case or the end of the cylinder (I like the case, because it is more rigid) and not have to find out if he tubes will be damaged....
Paul