I currently have a Sleeping Duck king mattress and Base but I was wanting to upgrade the base to an adjustable base - OneBed or Sealy probably. Disappointingly after speaking to SD, they told me that their mattress would not work well with an adjustable base and may damage the springs. So if I was to change to an adjustable base, I would need to change my mattress also.
King adjustable bases nearly always comes as 2 x long singles. Considering that should I consider getting 2 x long single mattresses instead. I really like the idea that my partner and I could then adjust our sides differently. However I've hated in hotel rooms which have had 2 x singles a lot of the time you could feel the gab.
What would you do?
I wouldn't get an adjustable bed unless required for medical purposes.
For twin beds, you usually have a topper over the top if joining them together; the quality of the topper will determine if you notice the gap.