Pointers to 14391 ISO/ESD for Download

I just restarted my Win10 Insider Preview desktop and got the dreaded "black screen with cursor only" and both rollback and image restore have failed. I need to perform a clean install, but so far I can't find a reliable source for an install file. The only one out there is the Russian .WZOR site and the download wants to take 50 minutes to complete (I've got a pretty fast 300-350 Mbps connection, so the delay is probably somewhere other than on my end). Can anybody recommend a good alternate source for an install file? All suggestions gratefully accepted.
TIA,
--Ed--

Because I was running the Enterprise version of insider on that machine the links at Windows 10 Insider Preview ISO Advanced have exactly what I need. Here's a screen cap of the choices on that linked page as they currently stand:

Turns out that this is just what I need and also shows me I got the build number wrong: it's actually 14393 not 14391. My apologies. But if anybody else needs this stuff, now you know where to find it (if you didn't know already).
Thanks!
--Ed--

Took just under 2 minutes for a 3.6 GB download at my best connection speed of around 350 Mbps. Now that's a heck of a lot better than 50 minutes!
--Ed--

Now this is Useful info...no need if having future problems updating to take the retrograde route....cheers Ed.
Note it is restricted to present Insiders.