Ooh. We scouting now. A spotters fee. Nice.
But, um, you know that Wattpad and Royal Road tend to attract the actually writer for free here (case in point). That is the majority that aren't on Paid.
Most of the paid contract stuff on Wattpad are locked into a set term. You might be lucky with those coming out of a contract. Since Wattpad only went paid a bout a year and bit ago, I suspect a lot of the high ranking stories, contracted, will still be on a contract.
Also, I suspect a lot of high read stories are being primed for Paid.
You have some stiff competition with incentives too. From what I gathered in Forums there and from WPNick, Wattpad contracts by terms and agreements. So, they are appealing to writers, since they are leasing a certain story for a set term under some fairly reasonable conditions. Edit: The lease continues on a contract too. But, according to WPNick, once the book has reached a required term, the author or WP can choose to opt out. This easy opt out feature is a big plus.
Unless you can offer a termed contract per book only, you're up against a wall.