When the word competition is raised, it matters little what limitation are imposed by the rules. Once you limit it to four channel radios and .40 sized airframes, people will go out and specialize their airplanes within the rules, leading to the most expensive conceivable versions of your "cost limited" legal entries.

What you have right now is a fairly loose limitation that allows up to a very nice sized airplane and everything below.

What I see occuring with the limitations you suggest is that every flyer interested in competition is not going to go and build a specialized "cheap" airplane.

In short, what I am getting at is that you will find much less participation than you think you will get. I say you would get 5% of your goal in competitors. It's nice bench speculation, but it's not going to fly.

On another note, the Senior Pattern Association is an established body that has a limitation imposed on the era, which compared to todays airplanes is much less expensive. Check it out.