Bonding two chins- Next Step

I have two females that I introduced and would like to bond. I've read many posts on this forum regarding the topic but would like to know when I should make my next move and place both chins in the same cage.

So far, I've done the following:

1. Quarantine
2. Cages next to each other
-No biting or scratching at cage bars. One chin seems to look for the other but mostly they ignore each other it seems.
3. Play time in a neutral area
-No chasing, no mounting, no spraying
-They have begun to groom each other. I did hear one of them make a squeaky noise. It didn't seem to be a bark or knack but not a normal "communication" noise either (well in my opinion.. but I also don't speak chin lol).
-They take dust baths together
-They jump in the same carrier to travel to the play area. And actually on accident, the smaller chin entered the other's cage and there was no bad interactions.

What other signs should I be looking for?

Again, when should I make the next move and place both in the same cage? I have a ton of new wooden shelves and toys coming in the mail next week and thought this might be a good time as the smells would be neutral. I don't have a brand new cage so I will have to scrub one down and add the new shelves.

Any suggestions are appreciated! Thanks!