I have the HC 50 custom reverb. I love the amp. I find myself wanting a 15 now though because of the volumes I usually play at. I can't help with The a/b though, but I wanted to congratulate you on a fine amp. Sorry for being off thread topic.
I use an Ernie Ball volume/stereo pan pedal with my Hot Cat 30, sending the left channel to one input and the right to the other. It let's me blend the two channels in any proportions or go strictly clean or gain channel. Way more versitility for me than an AB switch.
I still have a Morley AB switch the dealer sold me when I got the amp, but as I recall it made a noticeable click sound and I've never used it onstage. I've heard good things about the Divided by 13 Switchhazel and the Lehle AB switch.