[911pcars]

Without scales?

If so, assuming the chassis is not tweaked and the torsion bars are not worn, you could use the tripod method to adjust each wheel on one end of the car to the same height. Approximate chassis balance should follow, but you cannot validate unless you can measure each wheel. However, this method effectively eliminates any height differences caused by a diagonally opposite wheel (it's easier to correct two wheels rather than four).

You could remove the sheet metal cover under the front crossmember and lift from there. Here's what I did to avoid removing the cover. I installed layers of flat aluminum bar stock, enough to span the space between the crossmember and the cover. Thus when lifting under the cover (with block of wood), the force transfers directly up to the crossmember.

You could roll the vehicle forward/backward on your floor jack from this lifted position to settle the opposite end, the end you want to measure. Yes, removing the lifted wheels allows the vehicle to rest at an approximate rolling height. In addition, the closer the floor is to level, the better. Detach a sway bar drop link from one side to eliminate any existing preload. Using adjustable drop links avoids reintroducing preload if the ride heights are not exactly the same (assuming the chassis is balanced). Of course with the tripod method, you will only approximate chassis balance.

Hope this helps,
Sherwood