Nothing inherently bad about alloy covers, look good. There are venting issues, but those are usually easy to solve by drilling and taping the cover for a hose fitting and running the line over to the air cleaner. As to the type of gasket, that really depends on the type of seal surface on the cover. If it has a recessed channel then the silicon seal will be great, just glue it to the cover with some rtv and then install it on the head. Don't overtighten as the gasket will try to squeeze out. Most newer engines with silicon rocker gaskets have built in spacers in the attaching screws to prevent over tightening. If there's no channel for the gasket then use the cork gasket and glue it to the cover with something like Permatex. Don't use a RTV type product with the cork, the sealer will tend to push out much like the silicon gasket would and create problems. The T handles won't make any difference as far as my experience goes. They look "racy" but really aren't that useful, you won't be taking the cover on and off repeatedly as the racers do to check valve lash so standard acorn nuts or knurled nuts are just fine as well.