I feel/felt much the same way, going from hat views to TiR was a royal PITA for me, so many years of thumbhat views ingrained into my reactions. VR obviously looking behind yourself is extremely difficult, harder than RL IMO due to you can't use peripheral vision like you can with just your eyes, ie I can see my 6 in a plane with my head at 4 oclock or so, where as in VR it needs to be almost dead 6 to see 6.
The only tip I have I guess is to just get used to it. The hat view I use most while in VR is just the thumb hat down/6 view, probably 99% of the time it's the only hat view I need, but I do use the left/right 90 degree hat when I feel like it as well. In combat though, I just treat VR like trackIR, except say at a merge, I"ll flight the thumb hat instantly to get a track on the target in my 6 view, and when I start pulling him into my front view, I'll release the thumb hat and simultaneously start looking heads up with the VR to pick up the con.
It's a real conundrum for me, the game looks so cool in VR, yet admittedly I'm nowhere near as good while in VR when in fights. Yet. I keep switching back and forth, and probably should stick with VR. I'll state with 100% certainty that I can fight far better in AH in VR than I can in DCS flying jets, due to no thumb hat views incorporated there.