Good morning Doron,
Some helpful advice (I hope!)
Say you start with Tango Variation 1. Make any changes you see fit using the Sound Arranger and then save it to Panel Memory (PM) 1.
Now you can change the settings (as above) as save them into PMs 2-8. When you come to record your piece you can enter the variation required by entering it into Track 6 (the control track in the sequencer).
I hope that helps. You can contact Mark & myself at mark@gosling001.wanadoo.co.uk.
Luce