Hi KiwiXJ
As for me, living in Switzerland, we have Summer right now, but I like to think about winther any time...
I've heard of Problems having chains on front tires on full steering. Have an eye on this at the lower control arms and maybe fit a washer under the limiting bolt at the steering left and right.
I would run four chains, cause that gives you ample traction and you can take a pair on trails for additional traction in "summer". Right now I will start with one pair next winther in the 30-9.5 size. I'll see what that helps on the front axle. Knowing, that DC doesn't like to have chains fitted on the front axle, I'll have them on there for traction and braking support.
The chains should fit both tire sizes.
The size of the 30-9.5 is slightly bigger than the 235/75. I run a set of BFG AT 30-9.5 during summer, but will fit a "real" winther tire in the 235/75 size. This with the idea of having the right rubber compound for cold temps and the fine factory sipes allready. Bought my Jeep last winther with worn M+S tires. Amazingly they did a good job. But real winther tires are best!
As I've seen the year of your XJ is a 95 , you probably wan't have a full time High 4x4. I like to have this option on my '97. Always have my hand on the shifter to push it into N while driving on snow. Without doing this, the rear will push you further, because the breaking-power on the rear axle is limited. I made some "unnice" experiences on slippery ground, but snow often had been soft to the body
Hope that helps you in finding a good setup for your winther tours?!
Greetings from cheese and chocolate Country
Simon