We’ve been out about 25 times this season and the linear actuators have been flawless. I bought them from ‘Windy Nation’ they are used for sun tracking solar arrays. From what I recall they are rated at 250lbs each. So I have the potential to push up 1,000 lbs which is nice. I went with 20” based on the end height I wanted the tent to be off the trailer. It was dictated by the height of the trailer and the annex that connects to the tent. I’ve been really happy with the set up and wouldn’t change anything.