I went through the class a year ago May, my first bike was purchased last October and it is a 1200 sportster low.
I am 5'2", and i have had no problems with it, my nieghbor who went through the class with me purchased the 1200 sportster custom, though the two bikes are 5 lbs difference, her custom is so much more top heavier then mine. she has to really give it a heave to get it up right.
the other reason i didn't go with the custom is the forward controls and the bars, my legs and arms were straight out, i do plan on highway pegs for longdistant traveling.
Have your wife sit on the both the low and the custom and she will notice quite a bit of difference. MY husband deluxe isn't as topheavy as the custom.