I had my 170 weighed a couple years ago. Local A&P with load cell type scales that were about 12" square. Scales had built in ramps and chocks for the mains. No need to jack the mains, just roll it on. Load doesn't change a lot, and they don't move outboard like when you jack up one leg. Raised the tail on a hand crank forklift thing with the third scale on the forklift plafform. Mains don't move. Need to raise it until the reference is level - on the 170 this is the upper door sill- tailwheel goes up higher than you think. Get it level, read the numbers, do the math.
All pretty easy, really. Except watching the tail go up on the hand crank forklift thing.
Want to do a quick calibration check? Stand on each scale in turn; you might not weigh what you though you did, but the scales should read the same.
Good luck.