This must be a problem that has received much thought, and I suspect, some novel and innovative solutions.   I drove into my friend Devon's shop today with my big Thule box on top of the poptop.  He is a relatively new owner of a Westy who has recently installed racks and Thule on his van.  He asked me if I had trouble lifting my poptop after having intalled the Thule.  I told him that it was clearly more difficult to lift, but really not that difficult.   He then asked me if he could try to lift mine, thinking that I might have some secret device that made the lift easier.  As it happened, he couldn't lift mine any better than he could his own.  The reason was fairly obvious.  I am 6'3" 210 lbs., and Devon is ~ 5'10" 160 lbs.  Devon told me that he can only lift his with the help of his wife.  I realize this might be a great bonding possibility between them, but he's not that happy about not being able to use the poptop when camping by himself.  What do all of you smaller folks do to solve this problem?  Among this group, I'm sure you have arrived at many great solutions to this problem.  I'd love to hear about them so I could pass the info on.  
Tom LaLanne