I don't know about 5% per month, but then I don't operate with a bank myself. But I know I have adequate betting resources to cover the worst runs should they ever happen.
I've had a look at some of the pick four results given in the recent news on this site with the accompanying ratings.
What it tells me is "You can take a horse to water but you can't make it drink."
Most punters I suspect will continue to lose no matter how good the information they receive because they want to feel comfortable with their betting. To do that they all bet alike. That's why there are so many false favourites and false short priced horses.
Punting on horses is a negative sums game. You can only win at the expense of losers. It's because of all the losing punters out there that I can back plenty of winners at lucrative odds and get huge overs for my exotics plays.