I carry a 6 ton bottle jack and a torque wrench just in case. Never had to use either on the road. No problem with jacking the front but the 6 ton is marginal for the rear due to the much higher load, even with the jack positioned on the axle near the wheel. The only time I jacked up the rear was to change the brake pads and IIRC I used a short length of pipe over the jack handle for extra leverage to pump the jack up.
The biggest issue I had with the dual rear wheels was that they had rusted to the hub and no amount of prying and banging would break them loose. I finally got them loose by putting the lug nuts back on finger tight, dropping off the jack then rolling forward a short way and jamming on the brakes. That broke the rust bond. Before putting the wheels back on, I applied some caliper grease to the hub where it meets the wheels to (hopefully) prevent stuck wheels in the future.
