Paul, my mrs is only 4ft 9in, no joking. I fixed her up with a backpack on a trolley and I even fitted a hose reel to it. I fill the thing for her unless the container is half empty. She only ever does downstairs though.
The answer to your question largely depends on your round. Most of my work is very compact, loads of houses next door to each other. When you have work like this you just start doing the tops 10 mins before her. I allways drop back and give her a hand if I get too far ahead. [ I'll do these trad] As you point out, cons are a godsend as she can do these while the windows are dripping. The houses that have those little roofs above the downstairs windows are handy too. You can do the backs first and do the fronts after she has done the bottoms. If you have stand alone jobs then she can do any windows and door panells that don't have windows above them first. It's the same for guys that work alone when they have difficult access. I'm not going to climb over a gate/ wall 4 times, getting over and then getting back is enough. If a few drips fall after I have finished is something they will have to put up with, unless they want to pay extra. Hope this helps. Dai