I don't think clipping is necessarily a deal breaker. The big birds, like the Macaws, never really get to fly at the rescue. Not REALLY fly, anyhow. If you're a good match for our M2 who has been with us for 6+ years, I'm not going to pull the plug on the adoption because you clip your other bird. I'm not sure we have an actual policy on that. WE don't clip any birds when they're with us, but we have a couple of nearly blind birds that I would clip if it were up to me. We also had (recently adopted) a grey whose feathers wouldn't grow in on one wing. Some would feather cyst, maybe the others he was chewing off. I'm not sure. But if he were mine, and those feathers were never going to grow in on the right wing, I might trim the left wing back.
With any adoption you have to assess if you are moving the bird to a better place, or if he is better off staying in the rescue and waiting. If we waited for the absolute PERFECT situation, we would hardly ever place birds. Nobody in our area is a perfect fit. A more perfect fit would be putting the bird into a better climate so he can spend a lot of time outside getting sun in a large aviary. Clipping is a negative, but so are dogs, cats, work schedules, etc. It all goes into the equation.
Also, not totally sure, but I think the permit to keep a Quaker in CT requires that they be clipped. They're a problem there and the theory is that if they escape, the state doesn't want them to survive. I'm not sure about the Quaker regulations. We can't have them at all in RI.