I use both stars and bare emitters. My preference is with bare emitters since they are cheaper and I avoid an extra thermal barrier.

I mount emitters with artic alumina adhesive. Stars you can mount with any good grease like artic silver since most have most have slugs that are electrically inactive.

On emitters, you can also use arctic silver adhesive (not the grease). Like the alumina it is also a non-conductor. I believe the difference between the alumina adhesive and the silver adhesive is less of a capacitance effect. This has no bearing on LED applications.

For heat sink size, you need 9 square inches per watt of conductive surface with no fans.
I got some more pictures which I will post in a day or two. Progress is painfully slow.