PBP should put its own system variables first to ensure they are in bank 0.
From there, one way might be to declare a bunch of the biggest arrays
that are supported, alias the elements of the arrays once you've determined
where PBP put them (at least they will be continuous chunks).
From there, if you don't add any more macro type commands that require
more RAM for PBP, the locations of your arrays shouldn't change.