Just running the bass out the 2 outputs of my Source Audio Flanger pedal to a GK and an Ampeg has awed me. Either the GK or Ampeg on it's own sounds pretty good, the GK to 2 10s, and the Ampeg to 1 15. But together, wow. Now it's time to get serious about really doing some dual channel stuff .
Yes, it opens up a whole new world - or a rabbit hole! But it’s a lot of fun to try things and figure things out, and really be rewarded for it.
It’s especially cool using 2 different amps and different speaker sizes, that seems to me to get some really full sounds, each filling in where the other lacks.
If you ever have problems just using a pedal to split your signal, I would recommend an isolated ab/y pedal - plus you have the added control over cutting one signal out at a time to fine tune the other. The ones I have are Radial (switchbone) and Fulltone Truepath. The Lehle I have (1@3) isn’t isolated, but they have ones that are.