How long did older take to adapt to kitten?

[TimetravellingNarwhal]

We have a 7yo male cat and have just gotten a kitten (yesterday). Kitten is currently living in spare room, we've been doing flannel scent swaps. Cat hasn't reacted at all to the flannels. The kitten has been meowing since yesterday (not continuously or anything) and I'm certain older cat was able to hear but no reaction. Then he seemed to suddenly understand that there was another cat in the room, I think that he caught sight of paws or movement under the door. He hissed a few times and growled once then wandered off downstairs. From what I've read this is to be expected but just wondering how other peoples introductions went and roughly how long they tool until the cats reached a tolerance?

Our cat was 13 when we got a kitten. He took it all surprisingly well. They haven’t ended up as the type to snuggle each other but they touch noses on returning to house. The older one has never been the cat to have cat friends but younger one is so theres clearly a personality difference. The only time they fight is when they are waiting for dinner - we separate while eating as the older is diabetic and we need to make sure hes eaten sufficiently.

Yes we've opted for the dog crate for when out or night time. Ours are house cats! Yesterday I did plenty of secent swapping, and kitten stayed in my DSs room until this morning, with older cat having a sniff and sitting calmly by the door! Today we've opted to just let kitten chill and roam downstairs. Older cat has hissed and growled a couple of times upon investigating, but happily wonders back off when she's had enough and keeps her distance until she fancies another investigation. Both happily eating with bowls in the same room and litter trays in seperate rooms. Kitten is really not phased by older cat at all, looks at her as if to say "calm down lovey" 🤣😂 but again only really 24 hours since we've got kitten so all to still be expected, but definitely gone better than I thought it would anyway!!

@ilovesooty that picture! 🥺