i think 2 trs jacks won’t be enough. you will need 7 wires (1 per string plus ground) and 2 trs’s will only give you 4 (2 conductors and 1 ground per cable).
the subsix uses two four-connector jacks on the pickup side.
additionally on the subsix: as it is mounted directly to the body it picks up all body noise. i had some loose springs at the bridge which were introducing a rattling noise. not a big deal generally, but a noisy pot or anything loose might need attention.
using the gk saddles without their preamp’s and its eq is possible but i think you may not be happy with the quality of the sound.