Just chiming in to say:
Good on you for even attempting this, you've gotten further than a lot of other VR mods for other games.
For me, VS is all about immersion, so VR is a super natural fit. I would hope to be able to play VSVR one day.
To answer your question from a few months ago, for me the minimal viable product is that I can play the game 'normally' (i.e. M+KB controls) but with stereoscopic vision through the headset. The GUI elements can float statically in my face, that's fine, as long as I can see and interact with them. A nice example for inspiration is the Subnautica VR mod, which does exactly this (with game controller rather than M+KB), and is an incredible experience.
Next step up from that would be options/settings special to VR, like:
Manual height adjustment
Recentre view
Bindings for VR controllers (even without motion controls)
Smooth vs incremental turning
Visual compensation for turning, like total blackout vs vignette vs nothing.
Basic version of the above is those options being in a config file somewhere, that you edit outside the game. Bonus points if they're somehow in the game menu.
Then the big step up to 'native VR' level is stuff like:
Motion controls
First-person body animated
Custom GUI
GUI elements on in-game arms
Smooth vs incremental locomotion (super hard for some games, including VS I imagine)
Personally, I prefer fewer features and more stability to the opposite. For example, the Morrowind VR mod is incredible, it does basically all of the above, but you have to suffer through some jank. I would would rather lose motion controls and go back to 'click to attack', and NOT have the UI wobble and jump around, my arms twist into unnatural shapes, etc.
I agree with the comments others have made about hardware, realistically the target is probably Quest 3 until/if Steam Frame comes out. I have Reverb G2 and I play VR mostly seated because the cable is such a pain.
Anyway, hope inspiration strikes you again at some point! I'm definitely happy to help test if that happens.