I've been struggling since Beta 2 came out. My Apple Watch has currently 3.0 Beta 1 (14S5247t) but I am unable to install Beta 2. I can see and download the update after installing the profile on the watch. The watch reboots after installing the profile and seems to be connected to my iPhone (also on iOS 10 Beta 2). I've reset to new both watch and iPhone multiple times, tried not entering iCloud ID on the watch as I pair it to my phone, installing the profile to the iPhone as well, etc. It just will not get past the Software Update screen that shows that it's Downloading to Watch with "About 15 minutes remaining".
watchOS 3.0 Beta 2 Stuck on "Downloading to Watch..."
I tried it again last night and it went through. Didn't do anything different.