The vast majority of my play time with this combination has been mostly Acolyte based with a smattering of Strike Knights for durability purposes and then Necron Flyerwing (Scythes + Warriors, Staffteks). I'm finding it's quite solid but with the changes for 6th, not the army it was in 5th in how it played. I.e. it's much more of a hang back and shoot army and use Strikes + Flyers to grab far away objectives. The issue I'm finding is attrition over the course of a game can often mean I hold objectives on my side and my opponent holds objectives on their side as I only have a set number of units which can really push opponents off contested objectives.
So what I'm thinking is trying to replace the effect of the Strike Knights in my pure GK army (linked) with Necron Immortals. They're cheaper (squad of 10 is 170 compared to 230 w/Psybolt) and are S5 firepower (Tesla & Gauss have their own +/-'s) with a bit more durability due to Reanimation Protocols. If I was to reduce the number of Strike Knights I was running and bring in some Immortals instead whilst using other goodies from the Necron book – i.e. Scythes, Barges, Crypteks, etc. and using Acolytes to SUPPORT the remaining Strike Knights + Immortals, I imagine I'd be able to get a similar army style but with more versatility from the Allies. It all depends on the transfer of points from GK to Necrons though.
Unfortunately for me I've been busy of late – site and job stuff you know? So I'd love to hear the brainstorming ideas of the 3++ community in relation to putting such a 1750 list together. I've played around with the calculator but don't have anything really sticking in my mind. So let's see what we can all come up with and I'll get back to you with what I start playtesting for use!