Hi rkalish,
Question on adjustable bases and king beds. Seems that the most optimal set of beds is split twins on the adjustable bases to form a king size. We have a king size bed now - going to split twins will be a slightly different sleeping experience with the crack in the middle.
The adjustable beds can only be ordered in a split king version (there is no single king versions with the most common manufacturers) but the mattress on top of them can either be a single king size or a split king size. The two halves of the adjustable bed can be programmed to operate together with a single remote.
Of course a choice of a split king mattress is also an option if there is an advantage to you of being able to operate each side independently but then you would have to deal with the split in the middle as you mentioned and decide if feeling the split was worth the tradeoff of independent movement on each side. How much you would feel the split when the mattresses were flat would also depend on the specifics of the mattress and on how flush the top surfaces fit together. A mattress that has a more square shape with sharper (not rounded) upper edges with either latex or memory foam on top and that has no tape edge or seam on the upper edges would minimize or reduce the feel of any gap or split between them.
You can also get various types of "convertors" which fill in the crack in the middle and attach the two halves together such as
here
and
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but you would lose the ability of operating each half independently so you may be better off with a single king unless you want to keep the option open.
You could also use a single topper over both sides (preferably with the gap filled in) if the gap in between was uncomfortable but this would also eliminate the advantage of being able to adjust each side separately because it could damage the topper so it would probably be better to use a single king mattress rather than go in this direction unless again you wanted to keep the option of going back to a split king mattress open.
At one store they seemed okay with using a king size mattress and moving each side of the adjustable independently. If one side was up and the other down, the mattress was torqued and the lower side was slightly down hill.
I don't think this is a direction I'd be comfortable with and I think it would have a significant risk of damaging the mattress ... especially over time.
Do most people just go with the twins and let the adjustable beds work optimally, or are normal king beds used and one side may be up and the other slanted up?
While I wouldn't use each side independently with a single king mattress ... I think that the choice between a single king mattress or two twin XL mattresses would really be a matter of preference. I would definitely connect each half of the adjustable together though if I had a single king mattress and not use each side independently. Each option has advantages and disadvantages depending on how you feel about having independent movement on each side (or your own separate mattress that can also be moved if necessary) but having to deal with a crack in the middle that most people would feel if you tend to share or use the sleeping area in the middle for sleeping, cuddling, or other activities vs having a single sleeping surface without any gaps in the middle is one of the tradeoffs that each person would need to make for themselves to decide if the crack or gap in between was worth the benefits of having two mattresses that are independent of each other. It would really be a preference and lifestyle choice.
I would also keep in mind that if you have a split king option and want a sheet set that allows for twin sheets on the bottom (for independent movement) but king bedding on top (so you are both under the same sheets and blankets) that you will need a split king sheet set (two twin XL on the bottom and a king on top) or will need to order your sheets individually rather than as a set.
Phoenix