I saw a post (not this site) from "Twolost" while building their van that they were told 200# was what the electric scissor mechanism could lift.
Also shown on several penthouse tops (but not any pics at the SMB site) is a shock type of device...shown below. Looks like an air spring. I assume it is for assisting raise or lower the penthouse. Can someone explain its function.
Sorry to say that in the last 10 months the only SMB's I have seen:
One at a state park that gave us the idea to add a penthouse top
Many at the SMB Indiana plant
So still do not know much about them.