This is true. However if you wanted to have the clean sound as the base Rig, the only to currently do it would be to note down all the default values of the "gained" Rig, tweak it 'til you're happy with the clean sound, engage morphing, move parameters back to their previous state in the default "gained" Rig. It's a bit cumbersome.
I don't think you have to note everything. I would do it like this: take your solo sound as base sound. Change to morphed state and make a small change like reducing volume 1 db (maybe even this is not necessary but I can't try it at the moment) Then change to base again and edit it to your like. Then go back to morphed state and raise the gain back 1 dB. Done.