In January 2017 my sister and I booked a trip 60 days before last minute. It was easier because it was only 2 of us. I will say that people always cancel right before their reservation, so you're still "lucky" in that aspect, but a party of 7 seems tough even with the 180 day advantage. Remember there are other hacks. For example, if you purchase a Laundry's Select Club membership card, any of their restaurants (The Boathouse, Rainforest, T-Rex, Yak n' Yeti, etc.) will have to seat you within 30 minutes of arrival to the host station. You could check out their website for more details. I've also heard success stories with walk-ups and there are plenty of WDW restaurants that I'd vouch for that if you went super early for a dinner service or super late, I bet they could accommodate you (I have dined at The Wave so many times with plenty of empty tables).