Hi Tim and Laurie, A little late but I run Firestone Transforce in a 16.5. I went up to a 9.50 when I had to change out on the road and that was the only size they had all six tire's in. If you happen to have purchased this tire through Walmart you will be very happy with them.
The width of the tread and the side walls are taller on the 950's. Mine was 850's from the PO. I haven't a clue what they was from the factory but assume they was 850's also, as the PO kept this rig well maintained I figure he replaced them with the original size. His niece told me the old tires had dry rotted and she thought the ones on it was only five years old they looked brand new but I blew one out 20 miles down the road. the tire shop wouldn't even put the spare on my camper because it was over 15 years old and had never been on the ground. I ended up having to buy all six because I was 100 miles from home. That was my welcome to the vintage RV experience. Hope yours is a better one.