I intended to purchase ILL$ for ROTR when we were there two weeks ago. We were starting out in MK and hopping late afternoon to DHS just for Galaxy's Edge. I was successful in getting a VQ BG for Tron, but when I went to book ILL$ for ROTR, it was apparently already sold out for the day because the app said unavailable. I checked back periodically throughout the day and it didn't change, so I'm assuming the LL did sell out for ROTR that day.
We fortunately, had been lucky with low wait times on other rides throughout the day, so decided to just bite the bullet and ride SB for ROTR. We ended up waiting between 45-60 minutes, but it didn't seem too bad since we were passing the time with family we don't get to see too often.
At the end of the day, we got to ride everything we wanted to in both parks (even had time to jump on MMRR with minimal wait just before closing) and I saved over $100 by waiting in the SB line.
ETA: I read in another thread that G+ still had 2pm limitation for park hopping for those still needing reservations. I wonder if this also affected ILL$ and was the reason I couldn't get one around 7am (we had MK reservations that day). Even though I kept checking, it would maybe show as unavailable until 2 pm and then they WERE sold out by 2 pm?