refrigerated air driers?

There is a lot of information on the web about refrigerated dryers but here is the Cliff's notes version.

1) Doesn't matter where you put it. Closer to the compressor eliminates the potential for "slugging" the dryer with condensate that would collect in the system piping and then begin moving with high demands.
2) If you exceed the capacity of the dryer it will not achieve the rated moisture removal. Now if you are in a dry environment there isn't that much moisture to remove, if you are in a humid environment just the opposite.
3) I wouldn't run two units in series, I'd run in parallel. Flow splitting is the answer.
4) If the units are completely self contained and the refrigeration circuit wasn't disturbed by removal and they were working when removed, they should operate fine.
5) Unless you have three-phase power available, make sure they are single phase units. Nothing like a piece of equipment you can't use.

Good luck.