As far as I can determine from research, the only control line stunt kits released by Midwest after 1970 were the Warbird Series models. There was a 1/2A series of kits also, but I'm not too sure about the release dates of those, but the four I have in my collection were well after 1970.The designs in question, the P-63 and the ME-109, were published prior to 1970 and I have posted the issues elsewhere. I have not had time, nor the full size plan of each, to compare them one to one. But in looking at reduced copies of each that have been published in books, I believe there are significant differences in each due to production requirements, which changes the design, and thus makes them ineligible, in my opinion. I have the kits, but not the full size plans of the P-63 and the ME-109. As has been mentioned per the rules, it is up to the contestant to provide the proof that the subject is eligible. As it has been generally accepted to this point that the Midwest Warbird Series kits are not eligible, I would think that a comparison of the full size plans of each at the time of entry would be needed and sufficient. How well the do or don't fly isn't relevant. I love the designs, and I wish that they were legal. Just stating that they are doesn't make it so. As for the Ol' Doc, he must be remembering the P-63 incorrectly, because we know it wasn't published until 1968 or '69 and they preceded the kits. Sorry Doc! He must have meant the '70s but typed 60's instead.
As for the other Classic and OTS designs that may or may not have been altered, you'll have to take them up on an individual basis. Kits put out by today's manufacturers may or may not have been true to the original design, and again, you'll have to take them up on an individual basis. I believe the main criteria is the date of the design, the moment length, airfoil, landing gear location, and wing/stab areas, which are the main basis for a design. In my opinion, if any of those have been altered or changed for any reason, it's a different design, and as it has been stated and agreed upon, designs were changed to allow them to fit in a standard available box. If that kit was released after the deadline, it would be up to the contestant to prove that the design existed at least on paper before the deadline, if you want it to be considered for eligibility. And again, just assuming or speculating it was, doesn't make it so. and for one more example, it is generally accepted that Bob Geiseke flew a version of his Nobler before 1970, but it wasn't the same as the kit that Top Flite Models produced after the deadline, thus making the kit ineligible for classic.
Type at you later,
Dan McEntee