Well, after my first night with the G-System, I can second Toneseekers post, to the letter.
My setup is exactly as he described his, and it is working perfectly.
I unlpugged the MKIV's own footswitch, flipped the switch on the back to external switching, ran two Y cords from G-system's switch 1 & 2, into R1, R2, Lead, & EQ, put the amp in standby, and started scrolling through the relay settings until I found the desired effect. Here's my g-system setup:
CCCO = R1
CCOC = R2
COCC = Lead
OCCO = R1 w/EQ
OCOC = R2 w/EQ
OOCC = Lead w/EQ
The G-Sytsem allows you to save two relay settings with each patch. I setup a live starter bank as follows:
Patch 1 = R1
Patch 2 = R2
Patch 3 = Lead
Patch 5 = Relay Toggle (Switches between eq & no Eq for each patch)
I'm guessing that I could just move the cable from EQ jack and put it into the Simul/class A jack and use that instead of the eq, but I haven;t tried it yet.
With this setup, I can step on mod, pitch, delay and reverb or step on any of the three loops, or kick in the filter or boost section.
Tomorrow, I may get around to trying out some of the factory patches, but I wanted to get a good basic setup in the user bank, first.
BTW, I didn't have any issues with tonesucking. I went with the suggested 4 cable setup.
The problem is that there are so many areas that need attention, you really have to get your head around the signal flow, and make sure that each step in the chain is working at the correct level.
Once done, this setup sounds great.
One Important note for the 4 cable setup: The insert loop is off in all the factory presets, by default. You'll need to turn it on in each preset, or use the lock feature to lock it on all the time. If you don't do this, your signal bypasses the MKIV preamp, and goes straight to the MKIV's power amp. it took me a few minutes to figure out why my channel switching was having no effect on my tone.