I am curious to see how the piezos work on your bass!
I have tried 4 different sets of 3/4 strings on my Staggs and all fitted, if only just (stock, spiro, pirazzi, presto). Maybe the Innovations are somewhat of an exception?
In order to make the afterlength shorter on my Stagg I have thought of just taking the anchor block off and screw it on the bass just above the recess where it sits now. Maybe that could be a solution for you?