For jacking up both ends, unless you need all the wheels off, I would feel safer using ramps for one set of wheels and jack up the other end. One less possibility for tipping over. I have and really like the Rhino Ramps. Make sure you don't have any rolling-off-the-ramp slope issues if you do this.
If you're jacking both ends, I'm not sure it matters which you do first. Your idea about the front first being heavier makes some sense, and I guess I'd do the front first anyway so the rear parking brake could be set while you do the front jacking.
I'd jack the front and put on stands. Then jack the rear and put on stands.
Then go to the front AGAIN and jack it up just slightly, as the front stands have likely shifted a bit when you jacked the rear. Reposition the front stands to be perfectly centered.
Then get on under there and hope there isn't an earthquake while you're working.
If you can leave the jack in place without it getting in your way that would probably be a good idea too.
Just my (in)expert opinions. Don't sue me when you're crushed like a writhing cockroach below das German steel...