I've been doing some testing on Eye of Winter as its my favorite spell in the game. I dislike brands as a playstyle so Jung's Arcanist Brand build wasn't doing it for me (and I want to be more hipster).

Eye of Winter starts to reappear on screen at around +700% proj speed in game or x8.00 in PoB. There a few notable things about this. First of all, I'm only using ~20 Ramako Sniper tattoos, though your passive tree would become a bit inefficient to fit more. Second, I am using a 247 widowhail with a 73% proj speed quiver. Third, I am not using ashes of the stars or any alternate qualities on blood and sand or eye of winter. At 714% increased in game (x8.14 PoB) the eye of winter projectiles dissipate about 10-20 units in front of me, so only a slight amount more is needed. I'm only using 2 medium clusters as well.

Between all of the sources of proj speed you can get on quiver/bow/wand/alt quality with ashes, and extra medium clusters, its possible to get it to return without using widowhail, which would be massive for an actually viable build out of this. I'm probably going to mess around with CoC as wand CoC is my favorite archetype in the game. Ascendancy choice is weird, it'd definitely be either Shadow or Ranger based on tattoo positioning, but no ascendancy besides maybe assassin gets a full 8 points of value. Pathfinder would probably be the best if you go Original Sin which may be my end game goal. Trickster is generically good, Sabo has the cdr and triggerbots. Deadeye has mark effect and tailwind for self cast. PF has flasks and wither for OS. Raider is solid for self cast but a bit underpowered in general right now.

I whipped up a PoB that has x8.14 proj speed with 2 wands equipped here: https://pobb.in/ElXYacWmnDPU. Its based loosely off of my exsanguinate not fully ascended pathfinder that I've been playing ToTA and now doing dumb proj speed testing with until my internet gets installed in my new apartment and I no longer have to use my phone's hotspot to play. It obviously is not good or even viable in this state, just wanted to demonstrate the required proj speed was possible without widowhail.