Are you trying for a resort view RIV studio? I think you'd have better luck if you're willing to switch to preferred view at RIV. I had a resort view 1 BR booked for a June trip. In early February, decided we wanted a 2 BR, and really wanted a lock-off, not a dedicated 2 BR (invited the in-laws). That means I needed a 1 BR and a studio available in inventory. I quickly determined it was very unlikely I was going to get a resort view 2 BR lock off and just coughed up the extra points for preferred view. Even there, I couldn't get all 8 nights I wanted and had to spend a few weeks with waitlists and website stalking.
That said, you're only looking for a couple of nights, so if you want to play the
DVC slots game, go for it! When I've stalked the website, I have seen availability change at all times of day. You can take screenshots each time you check, and you'll see days change here and there all the time. I've never discerned any pattern personally.