...probably better to work in non-facing pages for something like this, do as a complete spread, so two single pages the full width...
...just make a spot color guide (so it doesn't print), name it 'trim guide only', set to overprint...
...position perf guide and score/fold guide the same way, unless you have the perf as a printing item already...
...just ensure they overprint, whatever marks you do, can be useful to have marks in the bleed margin (1mm) set to registration...
...on your print order, make it clear as to the dimensions involved, and send a mock up...
...as i work in a print environment, this we have come across before, and always been set up as a 'complete spread', two single pages...
Andrew