I just used a racing jack. In most cases I find the ramps to be unnecessary, but then again, I have 2 hydraulic racing jacks to do it. For this job, I only used one on the jack point under the front drivers side support.
The jack point is right under the place where you put in the tire changing jack, but I wouldn't recommend using the tire changing jack. Too many things to go wring with it in my opinion.
I would leave the car jacked up on one point for any longer than is necessary. I left one up for 2 days, and came back to a bent rim.
As for how high, the first one I did was probably jacked to 14 inches. The second time around on my friend's SDL, it was in the city, and I jacked it up enough with the tire changing jack to lay 2 2"x6" pieces of wood under it and let it down. Didn't want the car coming down on me. I found it easiest to work when I was laying between the jack point and the tire on the driver's side.

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Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic