Yes and just to add to the confusion, downstage is towards the audience and upstage is towards the back. Ha!
James, when you say you used the outputs from the back of the F1-X to connect to the two amps, do you mean the high pass and low pass outputs? It is only a single-channel mono preamp so the way it was connected in the top picture of this thread would have the bass and treble pickups summed together at the input - just the same as having only one jumper cable and the DS-5 set to mono.
But using the crossover in the F1-X is a cool way to split the signal for using a couple cabinets - or, as you say, maybe running effects only on the high pass side and leaving the low pass clean. That's a kind of stereo too but it's like a vertical one as opposed to left and right.
Really the series stereo output is also kind of vertical in this same way, it's not actually left and right either. Back in the day when I ran a stereo amp rig I would add chorus to the treble pickup only. I liked that it left the bottom end intact so the bass note would still be solid. Running the pickups through their own separate amp rigs is a bit over the top in most situations but it sure makes for an amazingly LARGE tone! Yum!
Jimmy J