I usually paint the engine covers, and base of the block, with the same paint as the rest of the tractor. But, I use high temp black or silver on the cooling fins. The tins cover nearly all of the fins anyway, so it isn't really noticable. This way, regardless of the paint type, I'm in pretty good shape.
I start by painting the fins, all the way around with high temp paint. Then let it cure for a day or so. Then you can mask the cylinder off and paint the rest WH red. it looks like this without the tins:

Again, with the tins on you only see a small amount of the fins, but it still looks nice.
Kevin