Just a thought go to a good hardware store, ask for fender washers they are thin and come in many sizes, they should have them in three inch (I think). They have a small hole in the center put 3M magic tape in the back apply your texture of choice. Once cured remove the tape and Tadaa a large neat metal base. If that isn't thick or heavy enough look at the ordinary washers ruler in hand until you find them large enough.
The regular washers are heavy and trust me your figure will not fall over, ever again, plus if your oponent is bugging you, you can whack them with that heavy base for an instant attitude adjustment. :lol: :lol: :lol: :lol:
Hope that is of some possible use to you.