If your "T" is as loose as you say, where you can actually slide it side to side some, I don't think it's going to swell enough to seal. It needs to be pretty snug between the carbs, tight enough so you can barely rotate it by hand.
Get that hand impact tool. It's a "must have" for working on bikes. You'll use it many other places on the bike.
Get that hand impact tool. It's a "must have" for working on bikes. You'll use it many other places on the bike.