Feel free to bleed your brake with up to 100% antifreeze. It doesn't seem to corrode the internals. After all, a great deal of the hosing on a car that it runs through is plastic.
Antifreeze, screenwash, mixed or concentrated, up to you. If you don't like the sound of neat concentrated screenwash or whatever you choose, you can mix it to 1:3, that's probably what it says on the bottle to use.