I might aswell add a reply here seeming that everybody else has.
I play the yamaha digital piano P80 and play in octave style (boogie woogie on left hand)and practice hours and hours on scales on both hands.
Have psr 2100 also for my arranger board.I dont have any problem at all in adjusting to the smaller keys directly after pounding away at the piano.I think your fingers adjust without even thinking about it.

If you try to practice finger runs without the use of keys,lets say on the edge of a desk at work and play 2 octaves starting in the exact position every time,can you say that you end the scale in exactly the same position,The answer is no.
So after doing this quick test it tells me that your fingers will adjust to any size keyboard within reason ofcoarse.
I find that the difference in the key down stroke more of an issue than the width of the keys,having said that I can still adjust to that with no problem.