Congrats! Love barenia/toile! And a pristine Omnibus! Lucky!
I'm a newbie too. I've been stalking this clubhouse for a while. Personally, I would jump at the glycerine treatment right away if I ever get my paws on a Barenia B (my holiest of Holy Grail bags, lol). Seeing Barenia age gracefully and patina over time is one thing but actually owning it? In an ideal world, I'd be as carefree with my bags as I want to be. But with the amount of time and money spent on finding B's and K's, especially on a harder to find leather like Barenia, I'd be more paranoid about damaging her in the ugly duckling phase. Having said that, by the time I actually manage to get one, my mindset might have changed and I no longer mind having to go through the ugly duckling phase together.
I think you don't have to do the treatment. Because it's a toile combination, it's not as much Barenia involved. This is one instance where I wouldn't mind Barenia going through patina naturally. It would complement the casual nature of the toile perfectly.
Here's my current Barenia obsession.

From the Socialites thread:
It should scare me, how dirty the leather looks, but I'm more inspired than ever.