If the two KPAs are connected via MIDI: Each KPA would need only one Performance Slot to mute it, if the Remote connected to the "non-muted" KPA is used to select a Performance.
The PC number for that slot could be sent via MIDI from any of the primary KPA's Performance Slots.
Correct me if I'm wrong, but I had the impression that the idea was to use the two Kempers simultaneously, with two different amp profiles in stereo, rather than to alternate between them. In that case, there's no need to mute one of them.
Nicky's method seems best: instead of splitting the signal beforehand, just connect the Kempers in series by running a cable from K1's Direct Output (set to Git Analog) to K2's input.
A serious setup that Ash!
Correct me if I'm wrong, but I had the impression that the idea was to use the two Kempers simultaneously, with two different amp profiles in stereo, rather than to alternate between them. In that case, there's no need to mute one of them.
Nicky's method seems best: instead of splitting the signal beforehand, just connect the Kempers in series by running a cable from K1's Direct Output (set to Git Analog) to K2's input.
Now where did ai get the idea that @ashtweth wanted to use them separately. That really wouldn't make sense either, since you could have all the profiles on one Kemper....
Doh. I think I got confused with the thread where a user wanted to use his Helix and Kemper together but separately.
@ashtweth don't bother with the ABY switch, @Monkey_Man had the optimal solution.
Now where did ai get the idea that @ashtweth wanted to use them separately.
Probably from the mention of that ABY switch. 
Hi Robrecht/Nightlfe /ALL
Guys every suggestion is great and i am going to mess with all of them
I could use both an ABY and Nicky's method, i am going to try both, i really appreciate the efforts and post guys.
Now imagine a 6505 in stereo from one cab and an Mesa in stereo in a another Cab.
Not to mention the ambient cross over stuff you could do.
ill make sure i get some pedals to do morphing and other stuff, no point just having 2 kempers for the BOOM 2 amps.
Gotta use all of it right?
No prob @Nikos and @LiamThompsonNext Step is for me to get a high end recording interface, so finally i can record and show you guys.
I still gotta save up for the second cab, i have an small FRFR i could hook up but i want to show you guys the Power of this with the 2 mission cabs
Does any one have any ideas how to have a third foot and more toes ?? 
Ash
No, but if you want a 3rd Kemper to replace the phantom middle channel (trust me, this is a psychoacoustic phenomenon - we imagine the centre based upon times of arrival at both ears), then I'd recommend taking the DI out from, say, the left-channel Kemper to the right-channel one, and then its DI out to the centre one.
This is sound reasoning IMHO, both for micro-timing reasons (ameliorating the left-to-right movement impression created by daisy-chaining the units left-to-right), and also because degradation of the signal through daisy chaining will cause, most-noticeably, a reduction in high-frequency content. Seeing as high frequencies disperse much less than lows (more directive the higher the frequency), it would help if the outside speakers carried the them to the fullest-possible extent.
Whilst the above suppositions are technically-valid IMHO... they're absolute bullshit in the real world, Ash, so thank you for reading, sucka! LOL
That said, if you were to add that 3rd Kemper, I'd definitely daisy chain the left to the right and finally the centre unit. 
