Here's some data someone might find interesting to use to tame the Shurflo pump when using a single M10 nozzle.
Pump is a Shurflo #8000-543-236: the cheesy bypass switch was bypassed pump was wired directly.
Water used for all tests approx. 6ft. hose 3/8" used for feed line primed first.
(2) Fluke 87 meters used and one Fluke 8050A meter used.
I'll just post the results without a current meter in-line since that is how most will wire their systems up anyway.
Current meters internal resistance and cabling did minutely affect the results so make sure you use good wiring practices when assembling any alky. system. 10 gauge wire should be good.
All flow tests were for 30 seconds to minimize on/off possible operator induced irregularities.
Pump to Source NO Resistor: 12.8 volts on pump source 13.1.
Flow was 14.0 oz.
Pump to Source using .5 ohm resistor: 8.5 volts on pump source was 13.25 volts.
Flow was 12 oz.
Pump to Source 1.0 ohm resistor: 5.52 volts on pump source was 13.4 volts.
Flow was 10 oz.
I am thinking a .75 ohm resistor of 50-75 watts would be nice for a first stage.
I think for testing a 1 ohm variable tapoff resistor will work fine for you to get the pump tamed and the flow you want for use with an M10 nozzle, it would also allow you to take a second tapoff for stage II higher voltage.
Should be available at a surplus electronics dealer either used or new relatively cheaply.
Then add another nozzle for WOT and full pump voltage and you are good for 30+ psi.
Good luck with your own DIY projects.
