Hey Angevin,
Something seems wrong, a 1000px render shouldnt be taking hours to finish. I run my test renders that size and they generally take from 30 seconds to 5 minutes to complete...(this is relative to scene and your pc, of course.) Your settings seem cranked up pretty high...in some places...not very balanced either.
I don't think there is any reason to ever have a minimum of 2 subdivs if you're using an adaptive sampler. And 24 subdivs is really high....and .05 is really low (not very balanced). Denoiser can steal a lot of detail, so it isnt a good idea to make it do too much work...specially if you're using irradiance map as you primary bounce. I find Light Cache of 1500 tends to be low for our interior scenes, although .05 sample size is a pretty high one. Usually don't go over -1 for Irr max rate...
Anyway, its a good idea to start with the built in quality presets, (the 'quality' slider under 'Renderer') Medium is a good start, try high if you think it needs it. Then only change one setting at a time and render a small region with the region render window to see if it helps quality without effecting time too adversely. If you're having crashes and long render times, good to try copying and pasting in place the whole scene into a new SU file. Sometimes there is just something corrupted in the file and this is the only/easiest fix. Since Vray 3.4, I'd say this happens to 1 out of every 4 files!!...yeah 3.4 is still pretty buggy...
If you want me to take a look, you can PM me with link to download file and I'll see how it runs on our machines...I'll even hone in some fast quality settings for you. Could give you a good place to start with your settings in the future.
Cheers,
GD