Cool, I'll start a thread on the PiAmp if there's anything interesting to report

Simon, one question about the compensated saddles (which do look like a good investment, especially at that price) -- do they have a slot for the string in them? The stock saddles do, but as far as I can do from the photos, the ones you linked to don't. If they don't, do you need to file one? Or do you just let the string lie naturally across them along the line from the hole in the bank of the bridge (I'm planning to topload) to the nut?