I will ditto the touringplans reservation finder. It lets you have two active searches going on at one time. A few weeks ago I got a text at 2am that a dinner at Akershus ressie was available at the perfect time! I debated rolling over and checking in the morning if it would still be there, but I knew I would never go back to sleep until I had it booked! So I logged in and grabbed it. Last night- again at 2am!! - I got a text that H&V PPO was available, so I again grabbed it and then went happily back to sleep. On my own, before I tried the touringplans finder, I have had luck grabbing a PPO BOG, no clue how, but boy was I happy!
Many people on here find something the day of, once all last minute cancellations happen. Just depends on your goals and touring style.