I've got the 850...
I went with cheap Adagio Flats... (the Harly B flats look very like the Olympia packaging) replacing the squeaky scratch phoz bronze but might be an issue with the shorter scale length.
Vol balance is 'prolly down to the piezo pickup bar under the bridge.
I removed a spacer packing shim, this allowed a lower action, but also cured the 'bridge roll' of the bridge blade by sitting further down in the block, pushed down nice and square, make sure the pickup bar rests flat and central, in contact with bridge block and bridge blade.
Some pics and blah blah, mind tends to be a corner noodle played mainly unplugged. I likes it.
Oh and pics please... tut tut... you know the house rules.