Tapping into GC power supply

[MikeFarad]

Hello,
I'm putting together a system for a friend based around 2- FE103's in TQWT's. I plan to put together a couple of Audiosector Gainclone kits to drive them, and I would like to incorporate a high pass section (2nd order S-K bessel, fo around 85Hz- he has woofers) to protect and clean up the FE103's. I also read that it's beneficial to add a low pass filter to get rid of ultrasonics. And as far as grounding is concerned, would I be correct in assuming that the signal ground remains connected to the GC board as usual, and the gnd from the x-over goes to power gnd on the GC board (as indicated on the schem.), rather than signal gnd to x-over gnd to GC gnd? Details are provided with the schematic, and I would greatly appreciate your expert perusal to see whether or not I'm on the right track. - Great forum - TIA