I am an absolute amateur, but wasn't vitrification about replacing the ice-crystal-generating water in the brain/body with a liquid that turns into a glass when cooled? If you can get that liquid into the furthest reaches of the brain, wouldn't you also be able to distribute coolant through its interior, turning the effective cooling surface area proportional to the volume?
In this case cooling speed would be limited by the coolant flow and its thermal capacity and conductivity. You would have to use the cryoprotectant has a coolant. IIUC typical cyroprotectants are not good coolants at that temperature range. Nothing can be a good coolant close to its own glass transition temperature, since by definition their viscosity becomes very high (solid-like) at that temperature.
In the past, the Cryonics Institute has had a policy that said that they would not accept anyone who is not a member. This has changed. The policy now is that someone who has full legal authority over your body can sign you up after you die. It costs $36,250 to be frozen if you are not signed up, which is more expensive. They also will not do anything until you have been on dry ice for 2 weeks after they have been contacted, so not being a member is more risky.
This is very important news for anyone who is currently cryocrastinating. It means that you can drastically increase your chances of survival without filling out any forms. All you have to do is tell a loved one you want to be frozen upon death, and that you would like them to take responsibility for making sure this happens. This takes literally 30 seconds. Do it now!
This news might also be a reason to not sign up right away, if you think something better (like radical life extension or uploading) will come along in your lifetime. We should discuss this in the comments.
Edit: The general consensus of this discussion is that this is a really bad reason not to sign up for cryonics.