I ended up getting a 9900K, the overclocking headroom just wasn't there with the 3900x (and most likely the 3950x)
I'm happy with my final O/C of 5.2GHz All Core, and it's pushing my dual 2080Ti's to their limits.
I found some cheap B-Die 2133 RAM and have it running at 3866 CL17.
Cache is at 4.8Ghz
2080Ti's are 2100/8200
The FX-8350 will be retired to a kitchen/homework/printing PC.