I processed bitcoin history assuming filters using with P=19 M=784931. 

Findings:

- Output script + spent script filters (Wuille’s (b)) have sizes of ca. 0.2% of block size.

- Output script + spent script filters (Wuille’s (b)) are ca. 10% smaller than output script + spent outpoint filters (Wuille's (a)). Savings here however trend lower since years.

Graphs attached.

Tamas Blummer