This would require:
1. A detailed log
2. An improvement to status page
or 3. Actions in detailed log

I think it's a good idea to make black list of checked bad proxies, so script don't have to check them once again.

Add application specific rules on when to use proxy. google proxymiser

First relay request should be established through proxy1, if proxy1 is still being used when second relay request comes in then another proxy should be used for that request

Create a specific log, to show target and used relays

To show relays or routes

Great tool, but too many people know about it !
You should speak much more about it.