My search skills aren't that great. I'm able to find stuff about time changes but not metal changes. What I saw was that 90 minutes seems to be the rule of thumb. We got moved 55 mins on departure and 65 on arrival, which didn't seem like it was going to get me far.
I was thinking about focusing on the equipment change, but it sounds like that's a no go too. Although I guess I'd argue that a change from a 767 to a 757 is pretty materially different from a change from a 737 to a non-jet. I'd guess they are pretty used to people who don't like to fly the turbo-props. I'm just wondering if anyone has any relevant experience.