You have obviously discussed this with your ENT. Did you discuss the Oscia system? This is the latest BAHA on the market. If you had the Oscia, it’s fairly flat on the scull. It doesn’t have an abutment. With this any hat would fit a lot better than the BAHA.
With the BAHA any hat that is a loose in the scull part should fit. I wear a beanie in the winter which covers my ears and processor and I don’t have any issues with hearing. In the summer I just wear a loose hat with a floppy brim.
@Raudrive when you have your K2 on what sort of cap/hat do you wear?