I stated earlier that I wasn't going to get a CBN wheel at this learning stage of mine but a few things have since changed. So at this point I would like to buy one but which one? Here's a list of limitations I've placed on my selection process, the rest are up for grabs.

8" wheel
1" arbor hole size with capabilities to bust down to 3/4", 5/8" and 1/2"
1" wide wheel ( I would like to still use the shroud if possible.)

Here's what I haven't decided upon and would appreciate comments or suggestions.

Aluminum or steel wheel
Rounded or radius edge

I understand one of the benefits of the CBN wheel is that more heat is absorbed by it than a standard grinding wheel. So wouldn't aluminum be better because of its greater thermal conductivity?