OK so back to report some progress. Here is what I tried:
Took extra care to get rid of as much yeast as possible before starting to dry hop. Soft crashed to 55, let that sit for a couple days, then dumped a bit of trub, then harvested a quart of really clean looking yeast, then dumped another 4-5 quarts of yeast before I got to beer. Did this over 4 dumps spaced out by an hour or more to give the yeast in the cone a chance to settle down into the plumbing.
Swapped out the 3" TC gaskets that came with the brink for the hard plastic PTFE gasket thinking these would provide better oxygen seal. Bobby was out of the EDPM one or I'd have gone with those:
3'' TC PTFE Gasket (Heat Resistant to 400F)
Hopped with cryo hops. Did two batches of 3oz each.
Flooded the glass and let it sit for an hour. Put my spunding valve on top of the fermentor at 5 PSI and pressurized the sight glass to 10 PSI. Opened the valve. No joy. Block of hops just sat there. Increased pressure and eventually blew a bit of hops up into the fermentor and was back to my push, flood, push cycle.
Then I remembered the new gasket and how similar it was to the teflon gasket I use to make the racking arm easy to rotate. Loosened the TC clamp that holds the "top" of the sight glass (top being the part with the ports) and gently rotated the sight glass 180 degrees. Did that again in 10 minutes. The rotating allowed the hop much to mix with the beer more readily and sure enough when I went to push this much back into the fermentor I got maybe 75% up in one try. I then repeated a quick flooding and mixing step and pushed it up again. Shot right up into fermentor. Closed the valve and repeated process. Only this time waited 30 min after initial flooding and started the rotation steps.
Only issue I had was when I went to purge the sight glass on the second batch, I still had some wet hop material in the glass and with my initial blast I painted myself and my ceiling with beer hop mush. Don't do that. Purging with just dry hops is fine but once stuff in there is wet you need to purge with the downcomer covered. Next time I'll try covering it with my 2" TC to ball lock gas post before initial purge.
Sorry no videos yet--too much going on to also try to take pictures. Next batch I'll try to get a camera assistant to help out.