11 inch medium Collar head with standard frosting.
This is the frosted remo head used on most bluegrass banjos. and what I recommend. It's a 11 inch medium Collar head with standard frosting. I've used these for years and they are the most popular banjo head in the world.
They’re known for their bright warm tone, vibration, and sustain.
If you are not sure what size crown to get, I recommend the medium crwon, that is the most common. 11 inch is also the most common diameter size and what is used on the vast majority of banjos. Banjos without an 11 inch head are normally antique or specially made.