Welcome to the forum!
I would say, just relax and give them some more time. They are still getting used to each other's sounds at night and your new glider is just settling in his new home. After the 30 day quarantine is over, take them both back to the vet to check for parasites. Once this is cleared, then begin switching the gliders sleeping pouches at night, this was they have to be around each other's scent. After doing this for a while, try switching toys in the cage and even swap cages so the other glider is in the other ones cage for a few nights or so, then switch back. If this all goes well, then move the cages relatively close to one another, but not close enough that they can grab each other's tails through the cage bars. This is when you should be looking for signs of aggression towards one another. If they begin crabbing at each other through the cage, just take it slower and continue swapping pouches etc.
If this all goes well, then you are ready for formal intros!! I did my intros between my gliders in the bathtub. It's neutral territory so no one glider can do dominate over the area.
Good luck!
And one more thing, are you aware that poor diet results in cracking and brown dis-colored fur? You may want to get your new glider on a better diet.