The only problem I ever had with more than 61 keys is my left hand kept thinking my little finger was resting against the edge of the keyboard, therefore, that was the C note - NOT! For me, it was a PITA!
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.)