It should be really fast (seconds). If it doesn't show up on Coinos and Amethyst almost closes the circle of sending a zap, there is something wrong on the connection string that you made on Coinos and copied into amethyst.
Discussion
Well, idk. I tried to zap you, it didn't show up on my transactions. AFTER that, I zapped two people, the Amethyst progress circle looked the same (as if the zap didn't finish or work), but those two transactions did make it into coinos.
Ok, now it worked. I just re-did the connection but I increased the max routing fee. I wonder maybe that was the issue? Originally it was the default 1%, so maybe it took it a long time to "find the route" and sometimes it failed? (Idk how lightning works at all, I just now some of my transferers from wallet to wallet faiiled because of too low routing fee.