Here's an example of an HX Stomp preset I use for low tunings, with the Poly capo settings. The preset uses bi-amping to balance the high- and low-frequency Amp sounds. Path A handles the highs, while Path B handles the lows. Fitting all this into 8 blocks requires two amps that don’t need much processing power, and uses stereo EQ to simulate a cab (not a stock Cab). Using preamps instead of amps would have freed up more processing power. The output Mixer can pan the two Amps for stereo imaging. A stereo Simple Delay provides a stereo output that collapses acceptably to mono. However, deleting or bypassing the Simple Delay for mono-only outputs sounds slightly better.
In terms of customing, deleting the Simple Delay allows using the Line 6 Electrik, Litigator, or Badonk for one of the Amps. If you remove the Compressor, now the Essex A15, both A30 Fawn Amps, Matchstick Ch2, Placater Clean, and Line 6 2204 Mod Amps become available for one of the Amps. If you also remove the pre- and post-Poly Capo EQs, several more Amps become available for one of the Amps. Your choices for the other Amp remain limited. It take some strategy to shoehorn all this stuff into HX Stomp. but it's doable. (Note: For those of you who have my book, this is described in Chapter 4 on Poly Block processing, and is LowPreset.hlx in the Free Files folder.) Hope this helps - HX Stomp can do a lot more than you might think at first.