I'm recapping the power supply in a tube amp, there are two cans at 200mfd @ 350. I have two new 220 @385 and two 250mfd at 500. I know I can use the 220 but is 250 too much?

Yes you can use the 250mfd caps no prob. Try to stay close to the 350 volt working voltage with your replacement. The higher the working volts over normal operating voltage the lower the value overall. All the best, Tom