Aside from touringplans alerts, there's mouseseats, wdwpassport and others. I signed up for free alerts at multiple sites.
I personally had the most success with mousedining.com. Sign up for the 5 free email alerts. If you really want Space 220, and possibly other hard to get ADRs, consider the subscription upgrade. I paid for 1 month (8 bucks) at my 60 day window, which included sms txt alerts to my phone and got I 90% of what I wanted. Have to be quick, when alert comes through click right away If you miss, just keep waiting and trying (others are also using alerts and or just checking - and sometimes even if quick you will strike out). Eventually you get it. Just takes patience. I was off property and found my options pretty poor - basically I was down to my 4th or 5th choice at each park......The alerts saved all my heartache and I got my 1st or 2nd choice within 2 weeks. I canceled after 1 month as I was happy with what I got. The best time though ironically is about a week or less before your trip as people cancel excess reservations and the alerts will go wild, so if you're willing to pay 2 months worth you'll likely get 100% of what you want, or just wait until 1 month before your trip to buy the subscription if you don't want spend too much. It was the best $8 I could have invested as I'm really excited with some of the places I got.