[kasey_junk]

I don't know of any systems that implement equal % matching algorithms but I'd expect it would encourage games where you just send in more smaller orders (hiding their relation to each other if you are particularly shady) so that you would improve your fill rates.

Your hidden book time auction idea is not one I've seen implemented. Again I think it would be very detrimental for price discovery but can't prove that.

Just trying to think of it as a market participant, how do I determine what price I should bid or offer?

I can also think of all kinds of ways for this system to be gamed. The first thing I would try if I were making markets in this system is to ladder small quantity orders right around the last trade price. Then when you get filled on these orders they would act as high/low water marks letting you zero in on the correct price.

Not sure why I would want to encourage this sort of gaming instead of an open book, but I'd certainly like to try it if you ever create your exchange.

[Edit] re-read original comment and realize it is not pro-rata matching.