My 904 pulled from a 318 question

I have a question to add to this conversation. If your using a weighted converter (like a original 360 or a welded 318) does it matter which flexplate you use? For instance if i weld weights onto a 318 converter can i use the 318 flex plate? Or do you still have to use a 360 flex plate?
The reason I i ask is i have my original 360 converter but my 360 flexplate got bent. But i have about 3 318 flexplates laying around.