By all means put them on now for 3 good reasons
#1 To see if they even fit the tire.
#2 To see if you have clearance
#3 just so you know how to put on chains
I was totally amazed last week when I saw 2 trucks head into the bottoms with the snow and wet weather we have been having. We walked down to hunt only to find the last truck stuck right above the middle pond.....and sliding into it. 2 hours later they where still there trying to dig out. We figured we would try to help if they where smart enough (A LOT of people aint!!) The driver did just what we told him to do and got out of the immediate mess they where in but still had to climb the hill. Now they mention they have chains and are wondering if they should but them on
Out of the 4 guys in the truck not one of them had a clue of how to even put chains on and / or what axle to put them on. When we went to put them on the front tires we found out they where chains for a stock tire but this clown had just put on new snow tires 2 sizes bigger. He had a couple of little binders so e made it work but guaranteed that if the came loose he was going to have to put new fenders on his new truck, we had to stop a couple of times to rebind the chains but got them out of there.
Long way around the barn here but please make conservative choices when gong into the back country and not only have the equipment to get you out but be able o use it!!