Actually, it might not be very difficult to slap together a pair of those templates if.......
I've discovered insulation foam and have been using it for EVERYTHING around the model shop (and the house too). I've gotten to the point with it that I think it just might be usable to fix anything. Like for example, the throw-out bearing on the wife's Honda is showing some looseness and
Anyway, I use my scroll saw on the foam and can whip out two identical templates like that in about 2-3 minutes.
Draw a paper template of one wing's airfoil view. (The tips are flat, right? So trace out the wing's airfoil using the wing) Position it on a piece of foam and draw it on the foam. Measure out where the top wing would be on the a/c in relationship to the lower wing and draw just the lower line of the top wing where it ought to be on your template. Stack two pieces of foam and run that through the scroll saw. Taa daa!!!
The foam is thicker than the templates I got in my WM Ultimate ARF box. So they're going to be easier to use than my thin plywood ones. So I've already cut out a couple of template doublers to thicken my templates so they won't want to tilt while I'm using them. Took me less than a minute because I already have a template to draw on the foam.
Since you're not going to have exact measurements for exactly where the top wing is to go, if I were you, I'd leave cutting the top wing saddle into the foam templates until you've got the lower wing on the fuselage and the fuselage to top-wing structure on the a/c. Then you can easily measure the distance from the top wing's leading and trailing edged to the lower wing's leading and trailing edge. Those two distances (which are probably going to be the same distance if there is no decalage) combined with a measurement from the lower wing perpendicular up to somewhere on the top wing's belly would give you a very good idea of where to position the top wing saddle on your foam templates. Obviously, using whatever measurements happen while assembling isn't what you want, so you are going to need help from someone who already has the model to give you the dimensions. hhmmmmmmmmm wonder if a WM Ultimate..... hhhmmmmmm
The templates really aren't a do-or-die requirement btw. But they're going to help bigtime to steady the two wings as you're connecting them. The interplane struts really ought to do a lot of the support work while you're aligning and drilling. Of course, they aren't going to provide you with very accurate alignment.
But having the foam templates ought to be worth the couple of minutes to make them.
BTW, while you've got the foam handly, whip out fuselage saddles to sit the fuse in while working on it. They take a couple of minutes to make and save a BUNCH of hanger rash and balancing the fuse in your lap etc etc. The foam cuts like butter on the scroll saw. Cut a couple of verticals, check out if they're tall enough, then glue a foam "foot" at the bottom of each vertical. Takes about 2-3 minutes for two. And you can sit the a/c into the structures to "clamp" them while the glue sets. A no-brainer job that takes less than a heartbeat and you got big-time valuable pieces that cost almost nothing.