RoA / Artillery Ballista tanky Deadeye

After reading the amazing post by u/metalonorfeed on tanky deadeye and seeing the changes for Artillery Ballista, I started to put this RoA/Artillery Ballista build together. It seems decent on paper, and should be buffed next league with brand new defensive layers that I'm quite excited about. If I can get it to a satisfying level, it could even be a good option for leaguestart.

Let's start with the POB:

https://pastebin.com/txAkXi7H

The build benefits from the tankiness with about 140k ehp and 7+ Mil dps. Do you see a way to keep the flask uptime and improving dps? I would love to have a cluster set up but we are stretched thin with all the resources invested in defence.

A few points to start the discussion:

- The full gem set up still needs refinement, there is space for hydrosphere and other creeping frost

- The main Ballista 6L is using ele pen as the build struggles with pen but it doesn't seem right

- Elusive is slightly misleading and would very rarely be at 210k ehp, getting Elusive on boots quick would be very valuable

- I am conflicted with the ascendency, the less damage on Wind Ward works very well with our defences, same with Focal Point but this leaves us with Far Shot that may not fit a Ballista playstyle... it looks like adding Point Blank on top of Far Shot would be worth it, and it feels bad.

- In a league start scenario the phys as ele damage taken seems a bit further away than armor stacking and fortify as a Champion, is the build straight up better as Champion? I know Palstreon has been playing with a pure ballista build bypassing RoA.

- Lastly, the bow and quiver are from a quick poe.ninja grab and might be inflating the dps, I'd take a more mid-budget weapon combo to better evaluate the build.

- I was earlier pathing to the dagger nodes converting them with a Lioneye's jewel but a more compact passive tree felt better, there is an alternate passive tree to look at.