Caution duly noted, Bob & Wes.
I actually brought up this topic with Keith Scott. He is the one who suggested a 1" stainless pole. He was thinking it would be a good pull up rod for when you are getting up from the bed. I asked him about 2: one on each side of the opening, and he thought that would be cool too.
It wasn't until I got to the boat that I remembered the lights & hooks. This got me thinking more about cutting windows in, which is why I asked about how much was open in the later models. Got a good view from the Hutchins site as suggested above.
I'd really like a compression arch or something out of the way, but not made by me, haha.
Keith's suggestion is to get a 2 x 4 on top of a bottle jack, raise the roof a tad, unscrew the bulkheads from the seats, and take them out. Do this when I have the stainless poles ready, one side at a time. He wasn't worried about spreading the load on the rim of the tube like I was, rather just make sure the cut is flat.
This is something I would like to be able to say presto-change-o and have it already done, haha. I will have to sidle up to this task, if I ever actually do it.