There's AC-61-65e that gives examples of signoffs. "I certify that Joe Pilot, PVT 1234566 has satisfactorily completed a flight review of section 61.56 on 05 JAN 2015." I'm not a lawyer but by citing the reg and saying you've complied with the reg you should be covered especially since that's how the FAA says to sign it off. Having a lesson plan you can produce for flight reviews, complex checkouts, etc that meets the details in the reg would be a good idea.
I never did 141 instruction but for part 61 I cloned everything in the student's logbook in mine. I knew guys who photocopied their student's logbook.