So the second hole on the PCB for the switch's lug2, the yellow wire, is P1 which is feeding lug 3 of the Drive...
P2 is the furthest left hole on the PCB (blue wire) feeding off Drive-lug2 but connected to 3PDT's Lug1...
My brain hurts.
I suggest:
In-Jack to a 3PDT lug2,
3PDT Lug1 goes to the Awful Waffle PCB's "In"
Jumper P1 & P2 on the AW board,
AW-board "out" to 3PDT's Lug7
3PDT's Lug 8 goes to Out-Jack
Jumper 3PDT lugs 3 & 9
3PDT's lug5 gets black wire as per build doc
3PDT's lug4 gets purple wire (switch)
optional — 3PDT's lug6 jumpered to lug1 (grounded in bypass).
Potential problems: "In" according to the wiring diagram in the build doc looks like it goes straight to C1 (10n input cap); P2 trace looks like it goes up to R5 220r as per schematic — if so, that would negate jumpering P1&P2.
That's how I'd try it, wire it up like a regular pedal as described above and ignore P1 & P2.