If C2 can only track manual trades with 98% accuracy, why doesn’t c2 just create a manual orders page on the c2 site and allow manual trading through this page? This will make the manual orders be sent and tracked just like the orders sent by one of the autotraded systems.
A fx copy trading site has a manual orders interface like this on their site. It has some other interesting features c2 could incorporate. For example you can stop a system from opening new trades but let it still adjust or close already open trades. This is useful when you want to phase out a system rather than stopping everything at once.