YOU have to have the same front and back... 28 0z is the easyest and best for any stroker. the 50 0z is a harder balance when you have aftermarket parts... but do able!! IF you have a 28 oz balancer and a 50 oz flywheel, he will HAVE to make the flywheel into a 28 oz unit!! Flexplate for the Auto... it will cost MORE in labor than to buy the right units!! your shop is right!! He sound like he is trying to do it right and save you a few bucks from the balancer..... cool??
Just me................................
Thumper