Changing wheels

The Pajero rim offset normally stops such good ideas from working.

Look at your Pajero rims and your present trailer rims, look at where the hub is located and then see if the same rims will fit the CT.

It normally isn't the diameter which is the problem, nor the disc brakes on your trailer, it is the wheal/hub geometry. Search threads on the Pajero Club of Victoria Forum, there were costings there on steel rims to Pajero 17 inch rims.
Without spending an onsecene amount of money on our Kimberly suspension, we can't use the same rims as with our NS Pajero.

Have you tried Fitting the Paj spare wheel onto the Cub ? You'l see then if hubs need changing , flares need fitting , ect ect.

I used some 17" ROH RTX rims on my Aussie Swag camper trailer. It was the closest I could get to match my NS Pajero. (I changed the rims on my Pajero down from 18" to 17" too).
Even though the offset doesn't match (30 compared to 46 from memory), I could still use one of the trailer wheels on the Pajero in an emergency.
The bore of the genuine Pajero rims is quite small - too small to fit on my camper trailer, which is why I couldn't use them and have everything match perfectly. The other downside of this is that I can't put my Pajero wheels onto the trailer, but I guess that it is more important to be able swap the wheels from the trailer onto the car.
I can't remember how much I paid for the RTX rims, but you should be able to get a quote from any tyre dealer.
Hope this helps.
Leanne

Depends on your model Pajero however you might think about changing rims on the Pajero if you can to a size more user friendly. I think that is easier said than done though.

On some models the choice of factory rim is a manufacturing flaw, in my view, and whoever made the decision shoud be shot.