Reply To: Two page spread, sort of!

If your full-spread patterns are to be removable (and usable!) each one must be on one side of a full double page. They won't end up that way if you lay them out in one INDD and send a regular PDF to the printer to saddle-stitch. So yes, you should make two files, one for the instructions and the other for the templates.

Coordinate with the printer about manufacture. Your templates would need to be collated with the instruction booklet, folded and, if you absolutely must, stapled into the center of the booklet so that they can be extracted in a usable form.