If you book your home resort at the 11 month window you will seldom (if ever) have a problem getting a 2 bedroom unit. The only times you may have a problem will involve one of the "specialty" units or views. Examples of those would be concierge at AKV, standard or guaranteed Boardwalk view at BWV & the dedicated 2 bedroom units at BCV that have two actual beds in the second bedroom.
Booking at 7 months is a different story - depends on the resort and exactly when you plan to visit. For example, getting a 2 bedroom in early December at the VWL is very difficult if you must use the 7 month window. Getting into one of the EPCOT resorts is difficult if you plan to visit during the last 3 months of the year. (The "specialty units" are very seldom available at the 7 month window). Those who are most often successful at the 7 month mark usually call day by day for the reservation and are willing to waitlist for the days individually if they are not successful on the first call.
January (after Marathon Weekend), May and September are the easiest months to book at 7 months . Summertime is easier than Fall or Spring Break time.
HTH.