Re: Switching to TG while maintaining MG skills?
I played match the first couple years after picking up the sticks, then spent the rest of my life learning traditional. The matched skills have never really gone away.
Non-scientific, mostly anecdotal observation: I'm of the opinion that if you can play traditional, you can also play matched. The left hand movements have enough in common that you aren't losing as much of your matched skill as you think by playing trad.
As an aside, I went to see Gadd play last summer and at one point, he executed this incredibly flawless, open left-handed triplet with matched grip. It's a move I've seen him do many times with traditional grip, but I couldn't believe how effortlessly he pulled it off matched. When I had the good fortune to ask him about it directly, he said he still only practices on the pad with traditional grip, never matched. So here's a guy who spent his entire playing career using trad and he easily pulls this difficult stuff off when he flips the stick over in his left hand, even though he doesn't really practice that way.
Then again, he's Steve Gadd and we're... not.