Here's a step x step of how I framed a barrel a bit ago.
1st joist levelled the front radius header, and then just fill in the rest. The smaller radius joist are just the inside diameter of the fascia.
The plans specd these joist so that hangers werent required every 8". Im a big fan of elimating mechanical fasteners where possible crrating direct bearing and fewer changes of material.
Notches aren't necessary but completes insulation baffles as we went so don't mind the over cuts please ✌