Hi Terri. I don't use a NxStage, but...
I did 3-1/2 hours when I was on dialysis 3 times per week. Daily, I do 2 hours (pretty much the standard for daily dialysis 6 times per week). I guess fluid gain will vary depending on how much you drink, but I try to keep mine under 1.5 kilograms per day (the equivalent of 1500ml). This is because with adding 500ml for rinseback at the end, this would give me a UF goal of 2000ml. In a 2 hour treatment, that would mean a UF rate of 1000ml/hour. That's getting to be a little high. My home dialysis unit doesn't want patients removing more than 1000, maybe 1100ml per hour at home, due to the risk of crashing from low blood pressure (that is, before I would have a chance to infuse saline). I also like to be able to drink a cup of tea or something during the treatment, so I have to leave room for 200ml. I do still have some urination, so that allows me to drink a bit more, in addition to the above.
My instructions if I have to remove more than 1100ml per hour are to not remove more, but rather remove only 1100ml/hour, and then remove the extra amount the next day. If it's too much to do this (such as after the lay off day), then I can increase my treatment time that day.
Now, personally, I find that with short daily dialysis, I can't really drink much more than I could on 3 times per week, simply because the treatment time is shorter - there just isn't enough time to remove more, and if I'm doing dialysis every day but one, I sure don't want to be on more than 2 hours! The fluid limitation of short daily is one reason I ultimately intend to go nocturnal.
I do my dialysis alone, without a helper, and I do have a fistula. I just make sure everything I need or might need is at hand before I hook up. The hospital provided me with a hospital bed type of table and I put everything on that. I've had no problem giving myself epo or venofer.
Good luck with the rest of your training.