I also have a converted pop up to sleeper shanty, with a similar distance to ice. I used a large pvc pipe with a 9" inside diameter. I didn't have a fancy shop or the tools for the job but a chainsaw sufficed. I left mine up about an inch and a half and cut two finger holes to pull them up. I'm sure they could have been engineered to sit flush with the floor and still pulled out easy enough but it was quick and I think it may keep a guy from stepping in a hole.