at this point, I may be still leaning to hydraulic ram type pistons, as the alignment seems to be the issue. I should also say this will be a soft sidewall, which gives me allot more play than a hardside, (nothing to grab).
I'm also thinking of using larger diameter pistons, like 2", and having the base be the full 4' tall even though the stroke will only be 2', this will give much more ability to stay aligned horizontally (or side to side) when the top is raised, as half the piston is still in the base (I know, thus far we're talking about vertical alignment,or lifting alignment (up & down), but the soft side should accomodate some play in that direction too)
I'm also thinking these will be 2 way pistons, or, power up-power down, as this will also hold the roof assembly down when in transit. I'm aware that (4)-2" diameter pistons will raise slower & require more reserve than smaller pistons. let's do some quick math, 1" radius squared x 24" stroke x 4 pistons =301 s.i. =1.3 us gallons, not too big a reserve tank. technically the 2 way pistons just displace fluid from one side of the piston to the other, but still, not a big deal.
I do like the idea of electric actuators, but all this input on alignment is making me nervous about this idea as I don't plan to mechanically connect the 4 actuators together.
the other thing to consider is the speed of the hydraulic pump, as I would like to move 1.3 gallons in about 20 or 30 seconds, I have yet to look into this aspect.
As of right now, I know where the pistons will be located, how they will connect to the top & bottom, & have some ideas on how to limit the 24" stroke (chains or threaded rod, etc.) but those details I know I can figure out later.
I want to get the walls & roof assembly built first, then decide, so I'm still very much open to more feedback.
By the way, I'm assuming the roof assembly will weigh about 300 lbs with solar panels on top, divided by 4 pistons is about 75 lbs per, very little weight for hydraulics.
Money really isn't the issue, as I plan on this lasting into our retirement, & I come from the perspective of doing this once & doing it right the first time, plus, how much would we really be talking anyhow, fifteen hundred to a couple thousand dollars max ?