Jerry alters a number of whistles to achieve a voicing he likes. I disagree with his assessment that his (Generation) whistles retain the original Generation sound. They don't, but that said he produces playable whistles in a voicing a lot of people seem to like.

Personally, I'd go to a shop and pick a nice off the shelf Generation out of a batch rather than have one of Jerry's but there's taste for you again, different strokes and all that.

He also does a sweeter voiced model 'the Blackbird' which is supposed to have a more bird-like character. It's main bonus is a better balance, volume wise, between the high notes and the lower octave, other than that the whistle has been described as 'very ordinary' (so you can question the premium you pay for having the work done).

Jerry is a decent guy and serious about what he does.