The Swift and the Gryphon are really very similar bikes. My goal with the Gryphon was really to take everything I liked about the Swift and put it in to a drop-bar rigid specific frame. If you could do the ‘blind riding’ test on a Swift set up rigid and with drops against a Gryphon it would be quite a similar ride.
The Peregrine is another step towards road-worthiness, plus the rack and mudguard mounts and of course classic lugged construction.
Probably the main issue for your immediate consideration though is that medium Gryphons are out of stock and I’ll not have more until around June unfortunately… So you might just have to continue to cope with two Singulars in the house 😉