I share your consternation. I feel judging at KF Nationals is a lost cause as so few people really know the cars any more. I have seen cars garner a silver award one year, then the owner corrects several items that received deductions, brings it to the next National and then it receives bronze! It is meaningless - I have no regard for it.
As far as modified cars go, I would not like to see them banned as it is another form of preserving the cars. They can't all be restored and I think bringing them back in any form is a good thing. The problem is how do you, or should you, judge modified cars? At a national, a restoration/preservation car is judged based on authenticity (even though some judges do not know what is authentic) whereas modified cars are judged based on Fit and Finish. If someone does a nice job of modifying a car, it can get 200 points. If a car is restored nicely but the restorer cannot find, or does not know (because as you pointed out, there is no list of guidelines available from the club!) which battery cables are correct, or which radio antenna is acceptable, well... that car gets deductions.
The one that really burned me was in Auburn, Indiana in 2004 - the longest distance award. It was asked who had driven the longest distance in a KF product and member who had a modified car had the audacity to stick his hand up! The car he drove had not one KF part in the drive train and yet he got the longest distance driven in a KF award! Figure that one out.
My attitude is, I'll make my cars the best I can, I'll bring them to the meets, discuss them, enjoy friends etc. but when it comes to judging, count me out. If I do have the car judged, I disregard it as it has no credibility. Look through some old quarterlies and see how many cars get gold one year, silver the next, bronze the next and it will amaze you. In my opinion, it is subjective and cannot be taken seriously.
When I work on my cars, it is because I truly enjoy it and it comes from the heart. When the day comes that I start doing things to it because I want some sort of award then lock me up.
That's my observation/opinion for whatever it is worth.