Adding the nozzle after the intercooler makes the most sense.
Let the intercooler cool the air some, then let the CH3OH+H2O cool it some more.

I like the idea of using small diameter copper tube, crimp the end and seal it with solder. Then drill a 0.5mm hole in it.
Found some parts on amazon that might work:

20 psi pressure switch
https://www.amazon.com/gp/aw/d/B00GBW3ZTY/ref=mp_s_a_1_3?ie=UTF8&qid=1473373463&sr=8-3&pi=SY200_QL40&keywords=lf20+pressure+switch&dpPl=1&dpID=41eznAeMxJL&ref=plSrch

100psi water pump
https://www.amazon.com/gp/aw/d/B016Q54D6Y/ref=mp_s_a_1_1?ie=UTF8&qid=1473373782&sr=8-1&pi=SY200_QL40&keywords=medog+12v+pump&dpPl=1&dpID=41g2IKs2xcL&ref=plSrch

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U.S. Army Retired