Here’s what I used for mine, it’s a black powder coated tank from Jegs. The part number is 555-51137. It is also available in polished aluminum.
It’s very compact and actually works. With the old street rod style vertical tank the radiator always had air in it and the tank was frequently empty. With the new bottle, the radiator is always kept full right to the bottom of the cap.
I don’t have a recent photo but here’s what the installation looked like before I removed the inner fenders:
