We have the same setup. Tweeked my neck pushing the top up with my shoulder. I really needed to find something other than my shoulder and neck to lift the top.
I really like the idea of creating positive pressure inside the van to provide some assist. Thanks Herb. I will try it next time. If you are not using Herb's positive pressure assist make sure at least one window or door is open. The effect of negative pressure on your ears is not bad but if you pull the top down without an open window the positive pressure can make it hard to hear for a few minutes.
Several years ago I tried to find a way to get the top up with as little pain as possible. My top has two Yakima bars along with 100W of PV panels. If you are going to be raising the top on a daily basis that is about all that can be on the roof. There is a 300# limit on the roof but even another 50# makes it hard to build momentum.
Head over to Home Depot or that other big box and go to where they have gadgets for pickups like tool boxes and such. One of the gadgets is made to hold things in place when you are driving around town with a bunch of construction materials in the back.
The device looks like a gray 1" tube with a "foot" on each end. It is made to stay in position across the bed and keep things from sliding around. You will also see a ratchet on one end. Home Depot lists it as the "Ratcheting Cargo Bar". URL is:
https://www.homedepot.com/p/Keeper-R...7059/207097432
It costs about $26. When you extend it be careful not to get some skin caught on the ratchet gears. It do hurt. Put the outer tube (black) foot on the floor and the inner tube (chrome) foot goes under the "Push Pad" just above your head when you crawl through the side door. Try to center the top foot in the middle of the push pad before you start using the ratchet. It is easy to do and the bar is just long enough to engage the spring assist. After several lifts you will find the balance point on the push pad.
When you have a few minutes unsnap the gray Naugahyde that covers the spring assist. Look at each end of spring and if it is like mine you may see a gap between the end of the spring and the trough it sits in. Find the 1.25 PVC caps and pick up 5 or 6. Also grab several feet of the PVC pipe. You can use them to fill the gap without doing much work.
While you are in plumbing pick up 8 to 10 of the same caps and a stick or two of the PVC pipe. When you get home and raise the roof measure the distance between the shelf that runs around the base of the penthouse and the material in each of the corners above you. Cut the pipe to length and put a cap on each end. When you have the top up the pipe and caps will hold the roof up and take the load off of the bars and springs.
Since you are sitting on the upper bed check out all of the bolts that keep the cross bars held together. I had one of the 1/4" machine screws break when I was in Yellowstone. It is really hard to get the top centered once one of the components break. Drove to south part of ID where Tom (member) helped me put another bolt in. Right after he put the nut onto the machine screw/bolt the one on the other side literally popped apart.
It was July and the hottest day of the year. Tom is a good mechanic and excellent shade tree engineer. He had to create a block and tackle of sorts and use the device to pull the top into place. Fortunately there was a tree 10" away. With one end of the rope on the penthouse top and the other connected to the tree it was easy to center the top at whatever level we needed.
Best of luck. Keep asking questions. Lots of experience here.
Michael Springer