Type 1 DTM shroud... what lower tin?

[Scotts73SB]

Hey Peeps! I got a question. I am currently running a type 1 DTM shroud and the lower tins i have on there are the flat square things with 2 tangs sticking up on each side that go between the 2 cylinders.
My question is.. I was reading on another forum and they said to use the whole cylinder shroud piece as seen here..
http://www2.cip1.com/ProductDetails....C%2DC10%2D5444

So.. should i ditch the little square dealies with the tangs and go with the whole shroud piece? I read that Jake R said that to make efficient cooling you need to make pressure.. so im wondering if i need both tins on there?
Thanks a million.
Scott