there are 3 things that affect how quickly it will hit,bottle pressure,line size,line length
plastic lines hit quicker then braided,they can also be a real pia
i had my solinoid in the trunck for a year,using plastic lines and the hit was pretty slow,with a short w/b bike this was to my advantage
a few months ago i moved the solinoid forward about 18'' and mounted it just behind the motor,between the shock and the frame,i used a standard,dual mount,i think,solinoid bracket,i used a longer bolt and nut on the subframe mount to attach the bracket,this quickened up the hit considerably,but it still isn't instant,with my current .028's it hits pretty hard in 2nd
on my other bike the nozzle is only about 3'' from the solinoid and that one hits instantly
solinoids really don't like heat,so thats something to consider before you move them