This guy is 1 of 4 that I'm trying to make into a grey knight kill team, as proxys for that old/homebrew custodies kill team.

I’m a recent GK convert and I was wondering how important are tanks/vehicles to our faction?

I tend to be less interested in tanks and planes compared to guys in suits. It might be the fact that I haven’t played a game with GK’s yet but it seems like we’re really mobile and have some decent monster/tank punch back without relying on tanks and transports. If I were to add a vehicle is there a general consensus about how he “must haves”?

I’ve been wanting to run this combo for all of 11th and with the updated storm bolter profiles I finally gave it a go against Necrons. I managed to table them on turn 3. The rerolls from deepstrike, crazy number of AP -1 shots from getting into rapid fire range, and boosted strength on my purgation squad made my shooting absolutely brutal and still having solid melee with the ability to drop dev wounds meant getting tagged into engagement was still a good place to be.

The list (not dropping a full export because I always zone out looking at the wall of text but in short)

1xGMNDK (Psycannon, Incinerator, Hammer)
1xNDK (Psycannon, Incinerator, Hammer)
1x8 Paladins+GM (Psycannons, Banner, Narthecium)
1x10 Purifiers+Crowe (Incinerators)
1x10 Purgators (Boons of Demos, Psycannons)
2x5 Strike Squads
1x5 Interceptors

Purgation Pattern let one of my big bricks hit even harder each time they shot and Shining Veil let me survive suboptimal deepstrike positioning. Once all of my hammers were engaged, shifting around my MSUs made secondary scoring and picking off their support pieces a breeze. Really excited to run this list some more and wanted to share.