I on a bit of break now and not adding any new cards, but one thing I did find useful when I was really going at it in preparation for the JLPT, was to add cards when I am too tired to review. It was the fun reward at the end of the day. I would crank some music, get into the groove and add a bunch of content from whatever book I happened to be studying.

Also you might want to consider being more generous with your judging. You have high success rates so you can probably get away with it which should cut your reviews down a fair bit.

Yeah, I've been doing that lately. I used to be really stingy with the 3s, and now I'm more liberal with them. I still don't give out 4s, but that's okay. With that 2-3 weeks I took off from adding cards, I'm down to about 70 cards a day to review, and that's with about 6000 cards in the deck, so I've got room to add a bunch more now, the way I see it. As long as I average 15-30 a day, it'll work out long-term.