As soon as I can get a new clutch, I will be installing an aluminum flywheel. I have heard whispers of people having problems with the bolts sinking into the aluminum, or loosening because of heat expansion/contraction. Does anyone have any experience with this?
I have a friend who can make me a large steel "washer" that would have holes in it for the bolts (to hopefully eliminate these potential problmes).
Would this be necessary or at the least a good idea? It would be very thin, so I don't think it would be a problem.

also...

Should I get a scatter shield?

Be carefull with aluminium. It is very easy to strip the threads or in some cases completly pull the threads right out if you over torque something. Get a good torque wrench (ie: a click stop) and do everything to spec. If the bolts you are using are the same material as the flywheel then expasnion/contraction will not be an issue. I've never heard of this happening, but I guess it is possible. Call the manufacturer of the flywheel and see what they say about that and the steel washer/disc you want to build for it. Good luck.

The flywheel is aluminum, the bolts appear to be case-hardened steel. When I hear back from the manufacturer I'll post anything interesting that they have to say.