Glad to provide some pics and data. The mounting is identical on both sides of the A214HW.
The upper brackets are mounted so that the ball is toward the ground. The ball is 1.25 inches from the roof rail top and 24.5 inches from the rear edge of the roof rail.
The lower brackets are mounted as shown in the picture with the ball located 10 inches below the side top rail edge. Note that is the "outer" edge of the rail and not 10 inches from the top of the flange on the rail.
I chose those dimensions because the gas shocks are 35.4 inches long uncompressed and 19.3 inches long fully compressed. I didn't want them fully compressed and I wanted them to provide some automatic lifting as well as some automatic closing which means the angle needed to be somewhere between 60 and 30 degrees. I think I reached a good compromise because it is easy to raise and lower. When the roof is latched the length of the gas shocks are approximately 22 inches.
Here's the process I used for installation:
1. Drill holes for the upper mounts while the roof is down but unlatched so you can see what you are doing. You may want to raise it a couple of inches with the actuator. I used the sheet metal screws that came with the mounts and coated the back of the mount with silicone sealant when I attached it to prevent water intrusion. Note the screw positions are such that at the location I chose the screws thread into both the rail and the wood behind the rail. The ball should be 1.25 inches down from the top and 24.5 inches from the rear rail edge. It probably doesn't have to be that exact but I'm an engineer so...
2. Attach the gas shocks so the extension rod is down and let them dangle. Raise the roof using the actuator (or by hand if the actuator is dead) until it is latched into place. Goes without saying that the trailer should be level for this, especially since you will need to finish the installation inside it anyway.
3. Temporarily attach the lower bracket to the gas shock and position it on the trailer side so that the ball is 10 inches down from the outer edge of the top side rail. Mark the mounting hole locations; you may remove the bracket from the gas shock if you wish. (FYI, I didn't provide a dimension to the rear of the trailer because it is curved.)
4. Drill the holes for the lower bracket where you marked them. I used #8 1.5 inch long stainless steel machine screws with acorn nuts to mount the brackets. Those are available at Home Depot. I used 1/4 inch thick MDF to make the backing plates that are on the inside of the trailer but you could use any wood you want and could even use wood screws into a thicker board; I just liked the idea of machine screws/washers/nuts. The backing plates are a little above the bed when installed. I used the bracket as a template for the screw holes in the backing plate. I used the acorn screws to prevent any sharp edges. I used silicone sealant on the brackets on the outside of the trailer when mounting them to prevent water intrusion. I didn't take a picture of the backing plates because it's a little windy today...and it's cold by Texas standards...and I didn't want to
. I can take one and post it later if needed.
5. Repeat the installation for the other side of the trailer.
6. Attach the gas shocks to the lower mounts. Disconnect the wiring for the actuator, loosen the nut at the bottom actuator bracket and slide the actuator off the bracket and let it dangle. At this point you can lower the roof; you will need to make the rear roof drop off of the front roof to do this and I use my pole to do this because I'm short. If you are tall enough you can probably pull down on the roof side handle to disengage it and the roof will slowly drop down. If you are short like me then the easiest way I've found is to stand inside the door and push up on the front roof while using a pole to pull down on the rear roof. I took a picture showing the small bungee cord I attached to one of the brackets on the inside roof that I use with my pole to pull it down. Takes very little effort and is MUCH faster than the actuator. Once the roof is down, finish removing the actuator and put it away somewhere. I left the actuator brackets on the trailer just in case I ever need it again; plus, I often hang a flat TV antenna from the upper one if reception is good where we are.
Note that this installation would allow you to still use the actuator if you desire; I don't because it works so well without it and I hate when the actuator fails. Also, I did some testing (and a little math) before I installed these and determined that 40 lb gas shocks would be about right. My math made me think 60 lb gas shocks might work but be much harder to close. So far the 40s have worked great on several trips including one just last week.