Okay, firstly, you do not have a balanced crank, you have a balanced rotating assembly. The counterweights of the crank have weight added or removed to match the weight of the pistons, rods etc. The crank alone is balanced to nothing.
Sell it as a balanced assembly as the pistons are no good for a stroker. Longer stroke means shorter compression height pistons.
Difficult to suggest stuff if you've already said you're going to use the same top end and a stroker assembly....