I always use reel clamps all the way down to reels I fish 15 lb test on. On my 30-40-50 lb stuff I have landed some nice sized fish like 70 lb bluefin on 30 and a estimated 220 lb plus thresher on 50 lb. Estimated due to release, I didn't want to mess around with a fish that size in a 21 ft center console and without a flying gaff. I much rather have a clamp on and not need it than not have a clamp on a reel and wish I did.
Leo, there may be other clamps made for the 30T as the stock ones suck but I was looking at this one about a month ago. Scroll to the bottom of the page to see the clamp.http://www.charkbait.com/cs/csrd.htm
Edit: I forgot to say Tiburon makes one too.http://www.tiburonengineering.com/products/reel-clamps