I agree, not much difference between the 600 and 800 as far as weight. My wife rides a 800 with a 155 and loves it. I have very rarely, if ever seen her use the sled to its potential but she is really confident in doing thing because she knows the sled has no problem taking her there. Probably my best advice to my wife was, "when in doubt throttle out". I have noticed many times when we need to climb up out of something and she isn't carrying enough momentum to get out, I will think she is stuck and then she gives it just a little more throttle and away she goes. If she hasn't rode a 600 to know that power she won't be any more intimidated with an 800. It will be a learning curve all the same. And she will quickly learn what she can and can't do. As far as starting the sleds they adapt. 90 percent of the time my wife can stand on the running bored and pull with two hands and gets it. On occasion I have seen her sit on the seat and sit up by the handlebars and then push off the footwell bars and almost fall backwards at the same time. This is usually towards the end of the day when she is tired.
I haven't rode with one girl/lady/man slayer that likes the 36" front end. You can't run a sway bar with it and it make the sled super unpredictable. My moms sled we bought the wider z bro a rms and she loves it. It's super stable and very very easy to ride. My wife's sled we just moved the skis out as far as possible and she is happy with that. We also are running powder pros on my moms and and now Mohawks on my wife's. Shock setup is very important, ski pressure will help a lot with how tired her arms get and if she can make it the whole day. We have found they tend to be happier is the front track shock is a little tighter than recommended for their weight and the back shock softer. That way when they are riding it tends to transfer the weight back and off the skis and it's not hard for them to steer. They usual aren't going fast enough to push through a corner because they don't have enough ski pressure. They have both conquered the art of leaning and how their body movements affect the sled in the powder. It's mainly getting up and down the trail that wears their arms out.