OTOH, why bother?

You have a $3500 arranger. And you want to cut corners on a $200 pedal?

Trust me, all seven are EASILY used up. Personally, I wish there were TWO FC-7 inputs, and I could still want more!

For me, personally, I lay them out (from L to R)

Var1
Var2
Var3
Var4 (all with Auto Fill on)
Lower 1&2 sustain
Sustain
Leslie Fast/Slow

but I am thinking of moving to more standard sustains, and opening up two slots for other functions - break/mute, or maybe Intro (which can be reprogrammed as Break/Fills) or Piano/Standard (if they ever fix the ACC cutoff glitch).

But essentially, the way I lay them out, I can run the whole arranger section 90% hands free. More playing time!