Main problem with an arranger (or any modern keyboard) is, how do you integrate the sounds that need effecting, and those that don't? Presumably, you are not using your keyboard for one sound at a time...

Once you start running through foot pedals, you have to be very aware of the gain structure, to make sure the foot-pedals are not hotter or softer than they need to be.

Personally, I think it is more important to have some good recordings of stuff run through the pedals, so you can start to try and match the sound using on-board effects and EQ. They are FAR more powerful that people give them credit for... For a start off, just rolling the highs off a lot of your sounds can go a long way towards getting that seventies 'keyboard through a bunch of pedals' sound. By the time you have run through a Bi-Phase, a Mutron and a couple of MXR's, there isn't much left (other than hiss!) over 10kHz...

This week I heard a great band play at one of my local watering holes.. Bunch of guys from Alabama, played for Capricorn back in the day, drummer played on a few Greg Allman things, that sort of bunch. Keyboard player had a Roland RD600. Not exactly state of the art. But he played it through a Fender Bassman rig! Now, I'll be the first to admit, the grand piano sucked. No highs at all. But when he put the Rhodes through it... 70's heaven...! Had an old Mk1 Korg CX-3 through a Motion Sound two piece Leslie, not as good as the real deal. But that Roland through the Bassman... WOW!

Remind yourself from time to time what the real stuff actually sounds like, and you have a FAR better chance of making your arranger's tones match it...