I buy my T8's from the guy who makes them in Finland. You should have no problems with a .30 cal T8 on 243. It is true to say that some folk dont like them, unbalances the rifle, looks ugly, they make a tinging noise. etc etc.
But for me they are one of the best things since sliced bread, just about all my mates have one or two on their shooting irons, and when it comes to novice stalkers and taking them out, with very little recoil and a good solid rest it makes it easier. I also believe it keeps the deer more settled and the ground itself.
Good luck.