Sounds like you have some good leads. I had a handlebar bag this summer that wasn't advertised as waterproof, but it pretty much fit the bill, and when I was really worried about it due to the weather, I backed it up with a ziplock. I used a Jones bar and didn't have any Jones specific gear: a Revelate sweet roll with a basic handlebar bag over the sweet roll made by Broad fork bags that looks pretty much like the Revelate one you mentioned. The BF bag never interfered with hand positions once I played with the clips, as there are a couple ways you can clip them on. It's darn nice to carry things like phones in a gas tank- same deal, fairly waterproof, better with ziplock backup in real rain, and incredibly accessible. One other thing I used cos it was a long trip and my Pika was small, was a dry bag secured atop the pika. This worked great. I just found a pic with some of these systems (the camo bag is the "handlebar bag/ BF bag I mention above). Good luck!
I couldn't post pic- too big but there are a bunch on this blog post with the bags and you can click on them to see closer. Not trying to self-promote!
http://southwestbackcountry.blogspot.com/2016/09/the-great-divide-northbound-la-manga.html