My platypus is leaking beyond repair and I am making a new gravity filter.

I found this 10 liter Boli water containers to replace my platypus.

The issue with the Boli container is that the cap is larger than the standard caps. Does anybody know a good source to get a nipple cap that will fit the Boli container. Or know a source for a lightweight nipple I could add to the existing cap.
I am also trying to determine the thread size for the cap. It is in between a 28 oz gatoraid cap (too small) and a 1 quart gatoraid cap (too large).

