those silicone seal on steel dont need the tabs , just lay them on the head and put the cover over them , but on a stock head i wouldnt use them due to the cast finish on the head sealing edge and with stock covers they just dont seem to fit the recess well , best with stock is the cork felpro vs-50156C glued to the cover , dont overtorque and do a retorque after a couple days .
champion heads mill that rough surface flat and you could run the T gasket but havent had much luck with them , my perferred choice would be cork or cometic (cut the tab ears back flush to cover because they dont give like the cork)
if you want thick cork use the felpro 1600 or TA performance carries a thick cork gasket