I have two 52" Model Perfections from the 60's and 70's. They were my first two 'real' hunting bows when I graduated from the old 'peppermint stick' solid fiberglass bows I had as a kid. The push to short recurves that occurred in those days was not good for traditional archery. None of the short, under 56", bows made by any of the companies were forgiving. In fact, they were just plain miserable and difficult to shoot unless you had about a 24" drawlength. My opinion is that the early success of compounds can be contributed to a great degree to how hard these short recurves were to shoot well. If we had been shooting 60+" bows, the rise of the wheel bows may have been different. In the early 80's when I was shooting my first 'good' trad bow after a short stint with wheels, I had the opportunity to shoot an early Allen compound. My recurve outperformed the early compound-Hands Down!. Sorry for the rant...but I feel that the manufacturers' marketing of short recurves and the archers of the times (me included) acceptance of the sales pitch created an environment that made compounds more attractive.
So as for the brace on a 52" Herters Model perfection? They are so short, and so curved, you gotta go somewhere close to 9". As George pointed out above, it is different for everyone, and as a rule the lower the brace height you can get to shoot consistently and quietly the better.
I knew an ole' boy who used to tease me about my Herter's "Super Stackers". The guy forgot more about shooting bows and hunting than I will ever know, and as usual, he was 'on spot' with his description of the bows. My advice is to do as I have, hang your Perfection on the wall and enjoy the beautiful and really cool curves of the bow, but don't expect too much if you decide to shoot it. Unless you are about the size the "Eighth Dwarf", you are going to really have to work at enjoying shooting the bow.
If you happen to have an interest in a couple of 'lefty' 52" Perfections; lets talk!