Will lead you into the logic of this solution......
So you have condensation in or on outside between filters Yes?
Cause is temperature of surface being below dew point and causing water to condense Yes?
Problem is Water Vapour Yes?
OK remove water vapour Yes?
Trouble is its in its little box with the dehumidifier and as soon as you open the box, logic dictates water vapor will again be present particularly if you shake it etc Yes?
What you need to do is make sure no water vapour gets to it as you assemble various bits Yes?
here is solution , put active silica gel into reasonably sized ZipLoc bag with camera, filter, MPPC etc Then remove 70% of air and SEAL leave for required period of time: then DO NOT OPEN BAG but if its only 30% full of DRY AIR you can manipulate pieces together without opening the bag , THUS assembling with no moisture. TOO EASY
Clive.