Okay, I took a taste. First, opening ruins the lid, so I'd probably have to use it all at once. At 4:1 with stock that's 5 cups. Not so much, but kinda pricy for a flavoring.
What brand did you get? My
Rogelio Bueno bottle I've got here says (paraphrasing) to add 3 portions of chicken broth (or water) to 1 portion of mole, then add sugar and salt to taste. Place over low flame (to avoid burning) and bring to a boil. May be served added to chicken, pork, scrambled eggs, tamales, enchiladas, rice and beans.
From my personal experience 4:1 would be too thin, and also I highly recommend chicken stock, not broth or water, although if serving with something other than chicken you might alter that.
I don't know about pricey. Here in L.A. my recollection seems to be about $4 and change for 8.25 oz. bottle. Our prices may be lower due to high Latino population and presumably high volume of sales.
It will be interesting to here about your cooking experience with the sauce and how it tastes over whatever you cook.
BTW it might taste more chocolate-y before it has simmered and mellowed. Or maybe you have a different brand. I usually get a different brand than what I have here, I think it was the Doña Maria brand. The one I have here is in a plastic bottle with flat crimp top. My usual brand comes in a glass bottle shaped like a little drinking glass, also with a crimped top, and yes you could save them until you have a set. I think I already said, serve tequila in them. They're about 4 times the usual shooter so your guests would be plastered they probably wouldn't even remember what the sauce tasted like!