Douga very stuck to cel

[Stormsky]

Hey guys, I recently purchased this cel from Kiki's Delivery Service which came stuck back to back with a douga from a different part of the scene.
https://imgur.com/a/6HURQWz
It seems specifically to be stuck by Osano's apron and Kiki's dress, so I'm guessing those paint colors became like glue at some point.
I've been trying to separate them using the method of leaving it in my screened porch room at night but it is not working great. It made no progress for several nights except for last night. it stormed and got so humid that I could start peeling them apart a little but it is leaving a thin layer of paper on the paint so I'm stopping to ask for advice.
Is there another easy and safe way to separate them that won't be as damaging to the douga? If I can't separate them without further damage, SHOULD I separate them?
I read the paper becoming acidic over time will damage the cel. If I continue with the same method, the front of the douga should be fine but the back will be thinner in some places. Is that acceptable?
Any advice on how to proceed with this would be appreciated, thanks.

[JWR]

I suggest following what is in this thread starting at the 3rd post by Backlotanimation who has many years of experience

viewtopic.php?f=61&t=28727&hilit=stuck+cel

[Stormsky]

I suggest following what is in this thread starting at the 3rd post by Backlotanimation who has many years of experience

viewtopic.php?f=61&t=28727&hilit=stuck+cel

That is actually the post I've been trying to follow, but maybe I'm being too impatient and pulling too hard or trying it too late in the morning. I guess I'll keep trying it but being a bit more gentle.

[Stormsky]

Update: So the gentle method is not going to work. It is just wrinkling the paper except for a perfect outline of the stuck areas.
https://imgur.com/bRwuEdt
So now I have a decision to make and would like opinions.
Should I separate it and damage the back of the douga more or just give up and leave them stuck together?
If I separate them, I should be able to flatten out all the wrinkles that are now in it from attempting to remove, but the back will have some thin rough areas.
Any thoughts on how I should proceed?

[D_Animation]

If it was me then I'd leave it or get it professionally done, but that's solely because it's a Ghibli cel and they're on the expensive side

[Stormsky]

If it was me then I'd leave it or get it professionally done, but that's solely because it's a Ghibli cel and they're on the expensive side

Then I guess that's what I'll do. Though I have a feeling it's going to be tough to find a professional. By how stuck it is, it's probably been stuck since it came out in 1989, so what's a little more time at this point. Thanks for the input.