Kitten to cat introductions going well. What is the next stage?

[KickBishopBrennanUpTheArse]

We have a 3 year old girl and were asked to take an unsocialised 8 week old kitten from an abused litter. She came to us last Monday.

I've been focusing on building a bond with her and she's gone from petrified to allowing strokes and cuddles in the space of a week .

We have been taking the cat intros very slowly because we've been focusing on building trust with humans. No face to face at all for the first three days, lots of scent swapping and fussing of older cat. We did a short intro on day 3 on either side of a stair gate with a towel over it with just noses showing and fed them both on opposite sides then removed kitten.

Repeated that on day 4 but without the towel. There was cautious staring but no aggression.

Day 5 the cheeky kitten realised she fitted through the bars and ran up to big cat, who did a hiss so we removed and backed off. Today they had about 3 mins of sniffing and looking about 2 ft apart but I stopped the kitten from getting too close because she's so lively. No fluffy tails or ears back at all.

I feel like it's going as well as it can but all the videos and guides I've found online pretty much stop at this point. What do I do next? When is it safe to let them properly have contact? And how long after that can you be confident enough to leave them together completely unsupervised?

Don't worry. I know the rules

No advice other than I'm very impressed with what you've done so far... and of course I'm cooing extremely hard over that photo

Actually I've just remembered our cat hated her brother when he returned from the vets smelling different. We tried stroking him with a towel and then giving her the towel to sniff. Tentatively it definitely helped and we did it a lot. We also tried a pheromone plug to calm her down. Don't know if that worked but worth a try maybe. I think slow introductions with lots of patience were the only thing we did until she got used to him again. Not the same scenario but perhaps the towel trick might be another thing you could try. We tried giving them a treat bowl to share (as they always did as kittens), that didn't work. She just ate and snarled in between aggressively eating the snack. Funny, but ineffective.

Sounds like it's going beautifully! Does Big Cat like treats (Dreamies, lick-e-lix)? If so, she could have a treat whenever she sees the kitten.

Make sure Big Cat has her own kitten-free food, litter tray etc (but it sounds like you know that).

Our Big Cat (4 at the time) astonished us by not just tolerating the kitten but actively seeking her out to play, in a rather galumphing fashion.

I'd forgotten, but effectively we did the 'towel trick' too, by swapping the room each cat was in so they could have a good suspicious sniff round.