All this GK talk has made me miss my GKs live. I switched to an svt for this reason. I had 2 800rbs I'm my rack. One for each 8x10 cab. I ran the out from my rack gear into a Y cable into both GK heads then each into their cab.
I don't know why but I was constantly having prob and usually just before we went on with something not working right. I swapped out all cables, ECT but was always something. The other issue was, the 300 watts seemed to start to distort cranking it to get them loud enough. I liked the idea of 1 amp for cab but of course this is 2ohm. Lately I've been thinking about the 2001. I have steered away from the higher powered heads (the reason is used 800s) because I need that rails tone and therefore Maxx the woofer and boost. Now I see GK will be revamping there line, we'll see. Love to get ahold of a 2001 and test drive it.