Underhood Add-ons for an F350 Diesel Pickup Truck

I have a F350 diesel dually pickup that I am attempting to install a continuous duty belt driven air compressor on as well as a water methanol injection unit. The pump head looks like a VW jug and is oiless. My questions are as follows:

A) I understand system will need a pressure relief or blowoff valve but:

1) Do i intall it on the tank

2) Do i install it on the compressor head its self and if so would it be installed in-line.

B) The water methanol unit I am planning to install would be basically a second windshield washer tank and pump that I would manually activate via toggle switch on dash. I plan on one injector for 70% Full throttle and a second to be kicked in at 85-90% Full Throttle. Therefore my questions are:

1) Where should I drill and tap for the injectors? I am thinking into the intercooler tube going from turbo output into intercooler?

2) And lastly where would i get two small volume low pressure injector nozzles for this? Any input on injector sizes or any of the above is welcome.