I would be glad to know URL's of available databases for testing systems.

They all come for a fee

Practical Punting Magazine I beleive has a service.

R.M.Plant & associates.
another called Price Predictor , both can be subscibed to, via PuntMaster website.

They can be good , it saves thousands of hours of research.But they all have their limitations.
E.G. The only horse with a 25% strike rate between TAB Nos.6,7,8,9. Most would have a problem sorting this, it will list every
25%er between those Nos. you then need to do the sorting from there.

The most sophisticated in Australia & the world for that matter, is R.M.Plant, the famous horse ratings family who along with Warren Block, were part of the imfamous & feared by Bookmakers,
Legal Eagles punting syndicate .
They won a fortune from bookmakers betting to value ,by creating a book against the Bookmakers & betting the overs, just like this site ProPunt aspires to.

I hope this answers you question.

Thanks for the info. Will check them out.