What difference did the carbon reeds make?

Does far less, if any damage than the steel reeds will do if ingested into the engine.
fiber reeds also help with power output as well, to more or lesser degree depending on which reed valve or set of reeds you go with, I am no expert with this though.

I'm a page behind [story of my life]. But could it be too lean on the idle so idle [with slide] has to be screwed up further than normal to keep it from stopping. Then when you've been for a run it just hangs at revs above idle & may come down slowly but not much.

Similar can happen if too rich on the idle where you need to screw it up to keep it idling safe but then once again after a run it hangs--but in that case it'd hang then slowly come down to where you set it.

the carbon reeds made no difference to the bike only peace of mind they wont destroy the top end. no performance change

I found a rich idle to cure the issue