Just drilled my frame for a stealth dropper. I think I’d prefer something that sticks on the outside rather than a proper grommet, just because I cut the slot only as large as I need and I’d have to make it bigger to take a proper grommet, further compromising strength. I drilled 2x 4mm holes almost touching and then filed them together into a slot of perhaps 9mm length.

Can anyone recommend a good source for such a thing?

https://sugru.com/

+1 for Sugru

Put some grease around the cable when you mould the Sugru over it, stops it from sticking once its cured so you can pull it out for maintenance etc.

Will try some Sugru.

My drilled frame hasn’t broken so far and 160mm drop is going to make a difference when I next ride some proper steep stuff.

Funny how changing a dropper post takes a bit of getting used to  The Bikeyoke lever is in a different place (using I-spec and one finger braking it’s a bit too far inboard so I might have to bring my brakes out a little) and stiffer then the reverb one, while the post itself has much less resistance to movement so I’m finding it less intuitive to drop to an intermediate position.