QEMU-KVM, GPU Passthrough, Windows 10 - Crashing

OK, so thanks to this post I've managed to fix the issue, at least in a test environment:
https://forums.engineerworkshop.com/t/fixing-gpu-passthrough-on-windows-10-vm-in-proxmox/207

The steps I took were:

1. Set <kvm><hidden state='off'/></kvm> in my VM config - this disabled the GPU drivers so I could boot into windows
2. Set the MSISupported registry key to "1" for my GPU
3. Re-set <kvm><hidden state='on'/></kvm> in my VM config

--

I'll rebuild my VMs properly next weekend (I've been running one Win 10 instance on bare metal) and, all things going well, accept this as the answer.

--

Edit: I rebuilt my VMs and the above initially fixed the issue. I run multiple different GPUs across my VMs however and, every time I changed GPU, it reset the registry key. I ended up replacing all my GPUs with AMDs which worked better (still have a reset bug, but at least they worked).