For anyone thinking of doing this, here's a quick rundown of the install route that I went:

1) Remove washer fluid tank, both pumps (one for headlights, one for windshield) and the sensor
2) Buy 2 washer fluid tanks from Princess Auto ($13 ea), a barb fitting ($2) and some chemical grade tubing ($7) (total: $35)
3) Dremel out the motor on the tanks and cut the plastic fitting
4) On one tank, drill a hole on the bottom for the main (windshield) pump and a hole on the side for the headlight washer pump (canada/euro)
5) On the other tank, drill 2 holes on the bottom: one for a barb fitting and the other to relocate the windshield washer fluid sensor. This means the stock washer fluid sensor is now a premix sensor! More more important IMO.
6) Make a custom mounting plate out of aluminum for both tanks and for the sensor bracket.
7) Re-use the sensor bracket as a mount point for the headlight washer fluid pump. This involves a small mutilation of the bracket but no big deal. See mid-left of the pic.
8) Throw it all back in the car and have fun with the OMP install itself, which is a story on its own. I'm just glad to have it done!

End result: washer fluid works, headlight washers work, low washer fluid sensor is now a low-premix sensor, and finally running synthetic oil. The only issue is the lack of a washer fluid sensor. Personally it doesn't bother me, as it's been re-used for something else and it's not going to be just another light on the dash.

Forgive the shitty pic. Better pics to come.

 

Nice setup! I like the use of the sensor for level control.

 

so there's premix in one of them? interesting. well done!