I have a Bodyglove 3mm - why oh why did I buy one with a zip up the back????
I find that a liberal application of vaseline helps prevent the zip sticking half way up. I have also extended the original pull tape (attached to the end of the pull tab on the zipper body)with a shoe lace so it's about twice the original length - this makes it easiers to transfer between hands or grip in the mouth while tugging on the neck to get the zip and layer underlying the zip straight and aligned. I also added a second shoelace to the body of the zipper itself (as opposed to the end of the tab that the vertical pull cord, with extension, is tied to) this second lace allows me to pull the zip down again if it gets stuck without having to drop the pull up zip. Also the zipper is designed to lock if the tab is in the down position - this can happen if you use the pull cord to pull the zip by its tab downward (am I making sense..?).
Beyond lubrication and modification I get comfortably into the suit, pull the zipper section taught and fasten the top velcro to keep it aligned, arch backwards slightly and pull smoothly up on the tab pull cord.
Perhaps a bungee cord hooked over that tab at the bottom with the other end under your foot would help keep the bottom of the zip under tension while you tug up on the top with one hand and pull the zip cord with the other - don't forget to unhook you bungee 'tail' before jumping in: you might find yourself back on the boat in short order... =8^O
Just the experiences of a newbie and amateur contortionist... %^S
Cheers,
K.