I'm a lousy musician, can't make the music I read transmit to my fingers very effectively, though I did use a lot of OTS because they usually sounded good, at least to me. And, like Don, but not nearly as proficient, I only play one lead voice at a time as well. When it came to the number of keys, I have played with 61 key arrangers for so many years that when I tried a 76 my fingers got lost. And, also like Don, I found that I mostly played the 10 to 12 keys right in the middle of the keyboard, and rarely hit any of those higher or lower notes.
I'm too damned old to learn anything more complex than what I have been playing for the past 4 decades.
All the best,
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.)