I used to make wine years ago, but never anything "professional". One thing
I avoided was the use of sulfites at the end of fermentation, as I have
several friends that are allergic/sensitive to them (causes migranes).

I recently started brewing 2 5-gallon batches of cherry (slightly different
ingredients in each batch as an experiment) with two friends. They'd like
to kill the fermentation to avoid cork blowouts. Options seem to include
adding campden tablets to the final rack in a glass carboy, or using other
sulfites at the end.

Any suggestions? One possibility for me is to bottle my share, then mix in
a sulfite to clean whatever is still in the carboy, and bottle it
immediately- but I always thought you had to leave it for 24 hours after
adding anything (I guess it gasses out of solution?). Maybe I could bottle
mine and backfill the carboy with CO2 from some suspended dry ice while
their sulfites clean up their shares?

Looking for any suggestions-

Thanks!
Keith