Bill,
A few years ago, when I had a PSR-2000 stacked with a PSR-740, I was burried behind the keyboards. Therefore, in order to compensate for the lack of view to the audience and loss of eye contact, I positioned the keyboard stand (double tier Ultimate A-Frame) in such a manner that I was sideways to the audience. This way I could see them, they could see me and they could see me playing the keyboard, thus no illusions that all the music was mysteriosly appearing from thin air or I was faking. It worked just fine, but setup time was nearly 40 minutes, and there is a lot of gear to both carry and assemble--not worth the hassle.
Stick with one keyboard and a simplified setup that can be done quickly--you won't regret it.
Gary
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)