The "First" construction article for PaPa Dave's PT-19 was published in American Modeler in Sept. 1960.
Republished in the '65 Annual as Ty said.
Best plans are CAD Drawings by Curt Contrada available from Randy Smith, possibly others.
Dave made slight changes to the model over the years, one was cutting down the amount of wing offset, IIRC. The last one i saw him fly in competition was powered by one of Stan Powell's K&B .40s (like Les Mc. used in the Stilettos). Dave and Stan are buddies.
I never have asked Dave about the Midwest kit, but he would be glad to converse with you if you contact him. Dave is a super nice guy, one of the finest people I have ever known. And yes I call him "PaPa" Dave when I see, or call him on the phone.
Big Bear