I guess I am getting too dense in my old age. I am missing the connection between elevator stall and titanium foil.

Titanium foil would probably need ribs to get the camber.
Properly ($$$$$) done, a block of it would be machined into the profile for the tunnel.
Getting a sheet 1 molecule thick would be a challenge...
But in essence the need to do this wouldn't exist as we know the limits of a typical microfilm model, and could adjust the tunnel speed to suit.
Getting a turbulence 2 mph flow, and a balance sensitive enough to measure grams of lift or milligrams of drag would be interesting.

These airfoils are quite thin- that was the why the foil gag.
We just got through using Mother Nature's wind tunnel to test some stuff-
One model a Mini 3D with AUW of 7 ozs and that included a 2 oz EFlite 370 outrunner motor -on a 9x 4.7
this was really a bad combo - the torque reaction and propblast simply twisted it abut 15 degrees upon application of power.
acceleration tho was spectacular.
I just retired the 370 from that setup---
what was really interesting tho -was a Knuffler design - with a tiny rewound CD Rom motor - the model -in still air - flies just like a very good 1.20 pattern design.
smooth- perfect slow rolls - nice straight pulls n pushes .
All this and no "airfoil" most would recognize - just 3mm thick, flat foam sheet .
The hard part is making it all free from excessive flex.
This is really fun stuff.

Working on a Convair Pogo made from 3 mm depron with a CD rom motor. Had to make a 9 in. glider to find where to put the CG. These little motors and foam open a whole bunch of new doors for experimenting. If one is going to experiment with 3D stuff, why not start with the original

should work - the big advantage you have is far better possible power to weight and extremely low inertia so a tip over is not a taxpayer burden--
If only we had power to weight anywhere as good in full scale --