About a month in some 1010 tts and I'm firmly in the heel slip camp. They're the perfect shoe but just not for me. Such a bummer. I'll try some half size down at some point because like I said, perfect shoe, but i haven't been much for jamming my feet into 11.5s for a few years now.
I’m in a similar way, I’ve also got the heel slip. Heel lock lacing helps. I went a .5 size down, and although I skated the shoe for awhile, for me, it was too tight.
In every other way the shoe was the most comfortable. I’ll get another pair eventually, from my experience I’ll go tts and just deal with the slip. Narrow heels, my only weakness*. Nike always fits me for this reason, but those dudes are whatever.