Don't bother messing with the type 3 cooling tins- the original type 1 pieces work better. Remember the fan configuration- on type 1 the air is coming down through the cylinders and heads while with the type 3 the fan is behind the engine and blowing air across. There is a thread on this subject on the Samba (although I can't find it right now) and there is even a VW technical bulletin advising not to install type 3 lower cylinder tins on type 1 engines.
And your engine needs sled tins and either heater boxes or industrial tins to send the spent cooling air out behind the engine so the heat doesn't get re-ingested by the fan and carbs (and drive temps up higher). I think this would be more important especially if you're doing constant slow (parade) driving. Al