Here's some photos of my setup:
I used a pair of threaded hooks held in place with a small U-bolt. I used scrap wood to make the clamping bar. I had to glue a shorter piece in the middle to clear the side of the keg as my stock pot lid handle didn't stick up quite high enough. I use washers and wing nuts on top of the wood clamp bar.
The flange gasket I used was:
Part number: 8516T23
Buna-N Flange Gasket 8" Pipe Size, 8-5/8" ID, 11" OD
$7.94 per Pack (Sold in Packs of 2)