I woudl like to add one more feature idea to the overall idea that might work with the existing subscription plugin, with added extra tip-post thinking.
A user credits up their sub account, i.e. via Sub 120 a year. (10 per month)
The site/admin has set all user sub privilege to allow 10% of that sub value used and distributed in tips internally on the discourse to user via post tips (and also user tups) by the subscriber.
If they want to tip more they can credit up there sub more, so say they want to budget an extra 100 a year for tips, they credit up the sub account in total 240, where at least 100 get’s reserved for tips or 112 including the 10% default reserve from sub total.
Running a whole transition via CC per tip would probably be too much overhead on various counts (but you might need that option also but it would probably be best to package as sign up for a subs with ability to to tip and get great content i.e. tips feature is bundled as part of the sub offer), and allowing a credit up system integrated into the already existing subscriptions system (plugin)
This would probably be the best course, or that’s my latest thinking on the idea and how it might actually happen. 
In this instance subscriptions work to support two good works:
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Subs support the site
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% of subs support user content creation (incentivises) and is user directed / decided.