Yeah 20% is the super high estimate. In all likelihood the chance APR would be pushed down to even 10% is likely because users love passive income. And the LP tokens are greatly hedged to the downside. That and 10% yield on HBD is already being offered so it can't really get pushed much farther below that (if at all).
Essentially it's possible (if not probable) that we could lock up to ten times the liquidity we put into the yield.