We have a 6ft zip and link so basically 2 x 3ft singles on a single divan base each, shoved together and then locked together, the base with U shaped clips and the mattresses with zips.
We did this because we stayed in a hotel when I was pregnant and despite getting up to go to the toilet several times in the night I didn't wake Dh. We actually removed the sheets etc from the bottom of the bed to see what brand bed we were sleeping on and discovered it was a zip and link.
The zips are on the sides of the mattress so you don't feel them and we bought our bed from a factory bed place where they make the beds on site. It cost £1k.
Dh is a lot taller than me and heavier than me, think rugby player build and there have been no squeaks from the bed in almost 4 years. It is very quiet
Getting the 3'beds that you make up individually without zipped mattress might be even better ... have stayed in a home in Holland with this set up - two duvets too and one comforter - and in one super king size bedframe ( think it may have been Ikea )