Sharpening larger pull reeds, pulling them forward, works. The smaller they get, especially on the small mid reeds (you can't use the hook on the majority of high reeds), you may pull these small reeds in, and let set with a thin piece of paper, and sharpen them, but give it a few hours and they'll flatten themselves, on their own. It's like pushing an open-gapped reed in, to close the gap. Flat it goes. You'll be better off taking them out and guess-working, and cutting the the front of the smaller pull reeds, than pulling them inwards.

Flattening is not sharpening. And that's what reed lifters (hooks) have proven, to me, that'd ehsy they do. Mishapenning of the tongues, will cause a psychosis of back and forth tuning. That is, unless your ears hear, what you want them to hear.

You can test this very easily, if you have a reed that you don't care about. Make sure the reed is firmly in place. Make sure It has a gap, by pulling it open slightly. Then push the reed in, with some sort of implement. Check the tuning before, and after. It will drop.

This proves that using a hook on smaller pull reeds, is essentially a failure.

From pre-war German reeds to modern Hohner reeds, to Salpa reeds, to Binci reeds. It's pretty much all the same, with fish-hooking small reeds, inward.

Except Italian ones have less of a chance of dropping tuning, pulling in the reeds. But then again, I've had my sh*t problems with Bincis and closing gaps. Especially scratching the backs of pull reeds with fine files, GENTLY. They will eventually make a gap, once the blue paint is gone. I'd rather carefully swipe the leather aside, and use a very fine grit, super thing dremel style bit, on the slowest speed possible, with the Black & Decker rotary. Only problem is, the narrower the slot, the more careful you gotta be.