Rick,
I have the Dometic Duo-therm Low profile 13.5 btu w/ heatstrip in my bedroom. I love it!! It has high, medium, and low fan speeds as well as high, medium, and low a/c speeds. Also has heatstrip that really keeps the bedroom toasty at night when the temps get down into the low 50's and high 40's. I posted a pic of it awhile back, will see if I can find it. As far as the side to side vents go, I prefer them. I do not like air blowing on me at night and by closing one side of the other you can control where the air blows at night. If you close the vents that blow toward the bathroom/shower and leave the ones open that blow toward the closet doors, you will be able to feel (while laying on the bed) the air as the closet doors deflect it back into the room. I am a medium to lite sleeper and I have been running the heat strip every night from April-May w/o any trouble sleeping. I have also taken a few naps during the afternoon while having the a/c running, as long as I have it on low or medium speed, sleeping is not a problem. High is a little too loud for me. The only problem I have found with the a/c in the bedroom is, my main a/c thermostat is on the wall next to the stairs. If I leave the vents open in the bedroom a/c blowing on high toward that therm. it makes the main a/c shut off too soon. I found by closing them off and leaving the vents that face the closet open, the main a/c will actually shut off at the selected temp and the air in the bedroom circulates just fine as I said, the closet door deflect it back into the room. Hope this makes sense....
As far as height goes, I am 13'3" and that is actually to the top of my fantastic fan vent cover in the kitchen. You can see in my pic it is the highest point on the coach even w/ the 2nd a/c. I bought a volt meter the other day and have been watching that while running the a/c's. I have 120-122 volts w/ just the fridge running. After running the main a/c on high and the bedroom a/c on medium(fridge is still on electric) I still have 118 volts on the meter.
Here is the link to the picture I posted awhile back. Scroll down through the thread and you will see it.
http://www.montanaowners.com/forums/...89&whichpage=2