Graham,
I suggest that you play along with a 5/4 song (like Take Five) and practice until you get the feeling. Keep in mind, however, that to play the piano part of Take Five you will need both hands playing a sort of counterpoint (to give that syncopated effect). So, if you are planning to play the melody with the right hand on your PSR 3000 you will have to rely on a good style, with a piano track faithful to the original.
However, as I said, there is nothing that can substitute playing along with the original song.
Have fun!
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.