This would be quite large but not too difficult to draw compared to some other circuits.
Now on the schematic..
Never seen this pedal before (not many infos) but I've found this:
http://www.effectsdatabase.com/model/sears/phasingpedalI assume "Q" is the Depth pot?
Are the original ICs LM324?
Do you know the original FETs?
Are diodes 2 - 6 1n4148?
I assume points marked 1.8V get connected all together (same thing for +6)
The Toe Switch numbering is not very clear.
I guess it's a DPDT like this: