I discovered this quite by accident.
In order to lower the top without having to use your head as theprop up
stick try this:
1) close all of the windows and doors to the van
2) release the rod for the pop top and wallah....a slowly very slowly
dropping poptop with an aircushion to help you roll up the canvas in time
without getting them pinched in the top.

That will be 2-cents

Malibu Tony  85 Westy 1.9 liter  8 degrees BTDC and loving it