I would try to take get them photo copied, (local kinkos or print service) if doing that, you can get them in digital format and print them out whenever you want and possibly change size if you wanted to.
i would definitely make some templates, a few ways of doing so is wax paper over the plans and use a permanent marker to trace another way is tracing paper, one way i have used which is much more cumbersome is using a piece of glass large enough to hold your plans and elevate it off the table and place a light under and you can use regular printer paper over the plans. just be careful if your using thin glass not to push down to hard. i use a glass top coffee table with a round shop lite under it. hope this can help. and side note i wouldn't glue the paper to the wood
Sign makers that make magnetic car door signs, plastic signs & cellophane overlays often use publishing software to take designs from a digital photo & reproduce it on almost any surface. Your local Staples or print shop can reproduce the image but might not be able to reproduce it on balsa. I’ve been considering the use of adhesive backed cellophane for transferring designs. Right now I’m still taping paper plans to foam board & looking forward to working on my first balsa build.
A digital photo of the fragile plans might save them from damage.