Hi Colin,

Your base sounds very interesting we would be interested in seeing pictures of it once you've made it!  We love craftsmen/womanship!

Our sizes are as follows:
Double 4’6″ x 6’3″ (135cm x 190cm)
Kingsize/Zip and Link Kingsize 5′ x 6’6″ (150cm x 200cm)

The radius I'm not sure of as the edges are slightly rounded.  I'd need to do some more digging next time I'm with our manufacturers to find a tool to measure this, but can certainly do so if you need this measurement.

There is an industry tolerance of up to 2cm in all mattress and base manufacturing. You will need to bear this in mind.  We try to keep as close to the stated size as possible but there is always a slight tolerance.

If you're making a zip and link version I'd advise ensuring that its maybe at the latter end of that tolerance due to the zips in the centre.  Also once you have your bedding on you probably want it slightly over sized than undersized.   Two singles would certainly be easier to move and shift around.

Probably the most surefire method is to wait until you have purchased your mattress before making the final measurements.  However I can understand this leaves you in a position with a mattress and no base.

You can see detailed pictures and size measurements of our bases here also Colin.

I hope that the advice in some part helps you with your project Colin.  Any other questions please give us a call.