Region rendering is very straightforward, you hit region button and draw region in VFB. Can you record a video to show how it doesn't work for you?
Regarding the internal res?Has an alternative been provided or?
From Corona 1.4 presentation:
Removed Internal Resolution Multiplier (this is replaced with highlights clamping option, and upcoming glare/bloom filters)
I'l try and make a video, but there seems to be a bug where in same cases the VFB overrides the settings from the render tab and in same cases its the other way around.
Example that just happened.
: render tab says render to view
: vfb says region
It will only render region then. ( even tho the main tab says view )
Now the other way around.
When I set in the main tab render to region. and drag a region in the viewport this will override the region I select in the vfb.
Not sure that's how its supposed to work...