Thank you all for your help. I am obviously still learning. I easily created my own user patch with two amp heads and only got bogged down when I realized that the combination of effects is literally infinite.
Here's what I did as I recall: I opened a patch from "Best of HD" setlist, say "Uber Wet". In the chain at the top right I dragged the amp to the top of the rectangle creating an opening for a second amp to be added and opening an Amp B window. Then I dragged another patch over, say "P75 Crunch" and dropped in to the Amp B window and it popped right in, creating a dual-amp sound.-- edit -- maybe I drug the patch up to the "blank" second amp icon?
I recall clicking on each patch individually listening to their individual sounds then clicking on the dual-amp sound and marveling at how much better it sounded than either of the two by themselves. In fact, I had a tech on the phone with me at the time and commented how easy it was to create a dual-amp patch using drag and drop.
I haven't been able to duplicate this since then, in fact all I end up doing is messing up my settings. I've had to reload the flash memory more than once to get back to the original settings.
Was that one time a fluke, a glitch? Or am I missing a step in recreating it? Put another way, can two single amp pre-sets be used to create a dual-amp patch via drag-and-drop?
Thanks