My preference is to rebuild the 6803 flippers with original hardware replacements to keep the feel of the game, but I can understand why others convert to different style flippers.
Here's the rebuild kits for your flippers: (Bally Rolling Stones 5/80 To Truck Stop (Upper flippers) 11/88)
http://www.pbresource.com/rebuildkit.html#KT-BFLIP04
I think I have a spare dual solid state relay board - will double check and let you know