Joining worktop that is 963mm wide

Hi,
New kitchen coming that has worktop that is 963mm wide, and they require to be joined at a left hand corner.

Looking at various worktop jigs and they all seem to come with pins at a set size for the depth of the worktop, e.g. 900mm, 1000mm.

So how would go about using one to cut such an inbetween size? Are there adjustable jigs available?

Thanks

Wullie