I took a hole saw to the last (most rearward) baffle, because it was the only one I could reach with only one extension, and that gave a change in sound, but not necessarily performance. The four holes I drilled in the first/front baffle did improve on performance and sound. Almost no pinking and the headers have never glowed red since. Well worth doing. I am still a bit nervous about drilling it out, completely, as it might be too loud.
I might drill four more in the front to see what happens.
I wouldn't bother with the rear baffle, if I were to do it all over again.
