I am not sure if it's worth while to do these mods, because the serendipity sounds much better in my opinion but the circuits are nearly identical.
To mod the serendipity to the original jack orman son of screamer specs:
c1 47nF
c2 47pF
c3 100nF
c4 220nF
c5 1uF
r3 4k7
r4 1k
voice jumper
q1 jumper
q2 jumper
d1-3 1n34a
also here are two other mods that I normally do on son of screamer circuits, I haven't tried it with the serendipity yet, but there is no reason why they wouldn't work.
Bright Mod:
c4 33nf
Fat Mod
c1 220nF (you can try anything between 47 and 470 nF, but I like 220nF for adding chunk with my p-90 single coils)
the serendipity is a great board for playing around with son of screamer mods.