Poston's has them too but again, I can't vouch for quality on that particular product as I haven't purchased any of them. Poston does have excellent customer service as I have bought many parts for both my TR and GS cars from them. I have a T-Top car too and if you haven't already done so, you should do all the adjustments you can as to trying to obtain a good leakproof seal. Another option is a low cost, DIY weatherstrip package that I think was written about (on that other board) by Red Regal T who is John DiCarlo. This recipe uses rubber goods from Home Depot or Lowes I think? Might want to do a search to check that out and I'm sure other will comment on these and other options. Good luck!
From what I've been able to gather from numerous posts, there are still some dealers that you can get the orig. GM stuff through. Although it seems to depend on where you are located. When I ordered mine a couple years ago, I was told that there appeared to be 2 sets left in Minneapolis, and all the dealers that mine could link to locally. But I have read of people still finding the parts at the dealer.
I have not yet installed mine, and have nothing to compare against, but I have read that nothing comes close to the GM as far as quality, and you get what you pay for. But speaking from experience with my Camaro, aftermarket seals can be good or bad. I got a set of soffseal for that car, and it worked great for me, where others have had fitment problems.
So, what does it all mean????? I don't know.... I feel fortunate to have been able to acquire some GM stuff. It seems like stuff from other suppliers can go either way.
Good luck in finding a solution that works for you.
*'84 Burgundy T-Type - Mostly stock, mods coming sometime soon
*'70 Camaro - Mostly in pieces....looking for time & $$
*Assorted other vehicles...
I just put new GM weatherstripping in the t-tops on my car. I ordered it right through a dealer and it was about $200 i believe. It appears to seal well after being through a heavy downpour and several smaller rains.