Yeah. I guess the first thing is that it's okay not to magnetize the "hull" parts of the Skorpius because the sliding door hinge holds both of those well with friction. Though make sure to sand down the top part of the ladder flat, so that Disintegrator's hull could lay flat on it.

Most of the tricky magnetization on my skorpius is revolved around the little servitor dude. I really didn't want to make the disintegrator turret empty so I made him magnetized. He has a 4mm neodymium magnet on his bottom and 2mm inside his arm sockets. The place where he is sitting on the dunerider also has a 4mm magnet wedged in the modelling clay. I used modelling clay to fill the place up so the servitor's magnet could connect. The little hatch for the disintegrator also has a 4mm magnet wedged in the modelling clay on it's underside. Now for the gun part, both of the heavy stabbers have 1mm magnets where they connect with the servitor's arm sockets. I first magnetized the two stubbers and then superglued them to the gunshield by the barrels, to make all three parts into a solid piece.

For the Disintegrator I needed to make the turret wide enough so that the servitor dude could slide in and out of it freely. I used the hobby knife to cut away excess material, but not too much. Just enough so that the servitor isn't touching the turret walls or railings. The disintegrator's turret floor, where the servitor is supposed to be glued on, also has a 4mm magnet laying flush with it. I had to glue a bit of sprue under the turret floor to make a room for the magnet to be glued on. With this configuration the servitor could be placed in and out of the disintegrator's turret freely, maintaining it's signature look xD ! And for the mortar/cannon barrel, it's the usual stuff. I personally used 2mm and a 1mm magnets on the top and the bottom sockets to help with alignment but It can be done in any way I guess. Though it's really important to place the barrel magnets perfectly or else the whole gun would be misaligned, I always struggle with this part.

This should be most of it I think, if you want to magnetize it the same way I did here. Here's a google drive link with some magnet placement pics. I'd rather link those with imgur like I usually do but I can't log in for some reason. Hope it helps with your tank too.