It's not a problem at all. You support the clamshell at the center right below the lock handle so the pressure is even on both clamshell hinges. I start supporting it with the left hand and lower the right rod first. Use your right arm to grab the rods as far forward as you can (the further away from the rod hinges, the better since you have more leverage/arm). Once you put the right rod in, use your right arm to support the clamshell, again around the center. Than take your left arm off the clamshell and use it to lower the left rod.

I had an Eberle for a year and had no problems with it at all in opening the clamshell myself. Keep in mind it's not a clamshell, it's a half clamshell that isn't very heavy, if you support the clamshell from the center so it doesn't twist at the hinges or forward of the hinges, it really isn't a problem. You can always mod it with gas springs but that is way overkill if you ask me. Modern trailers have gas springs mostly because it's a full clamshell and the top half of the trailer weighs a few hundred pounds.