W2 Heads on 1996 Magnum 360 Block

Probably no other option unless you rebalance it internally. There maybe other sources for flywheels. Check the net for places like McLeod, Hays, Centerforce, etc... For possible options.

10.5 would be correct and easiest. A 10.95/11 inch wheels like some big blocks have can be a pain not worth doing.

The Magnum to a neutral balance converter requires the stock flexplate or a B&M flexplate.