I found a solution. Effects loop always on but able to switch between channels
Use two instant commands per snapshot. # 2 pedal/external amp connection on the hx effects
1. Dirty channel with amp effects loop on -- Instant command 1 - Ext Amp None1 Instant Command 2 Ext Amp None 2
2. Clean channel with effects loop on - Instant command 1 = ext amp 2(tip) Instant command 2 = ext amp 1tip