Step 1: PLAN: Make a faceted circle. Inside a circle, use the magic wand set to make lines of a specific segment length to get your window pane width.
Step 2: Complex Profile of glass and muntins: make the profile from base edge to peak edge
Step 3: Complex profile of mullion. Using the glass complex profile as a guide [duplicate it], make the vertical segment.
Step 4: Magic Wand a complex profile wall to the faceted circle
Step 5: Place an array of short wall extrusions of the complex profile mullion radiating from the dome peak.
Dwight Atkinson