Had I felt he was comfortable with measuring, I'd told him the same
thing, but since he was asking, I made another assumption. Absolutely it
will be better to lay out the job, and any mismatch will be easily
compensated with the flex in the comosite treads.
The cardboard templates will be better if they are not cut out until
stapled to the new board, even then, one good edge wll be enough to keep
them lined up.