Then the airfoil plot should be relatively easy to find.

What I'd suggest is looking for one of the recent model airfoils that look similar and use it and it's supporting data. Or make an assumption or two about the NACA ones basing the guessing on the model ones.

We operate in less favorable Reynolds and it's often expected that we'll have to fudge for things like less lift generation and such.

And one thing to consider is if you design for detachable wings, some of those arrangements allow for trimming wing incidence. Bolt on wings that can be slightly pivoted on mainspar tubes for example.