i have the NOS 5177 Dry. the solenoids ground through the FPSS and the relay gets it ground through the ground of WS which gets its ground from the WOT switch. 1 activation switch controls a relay to switch it on. and one power wire out to the solenoid.
now i'm going single solenoid per stage. i just want to make sure i can leave everything as is and just add a relay and power wire to the second stage. and an activation switch to the 2nd stage which will be a manual control as long as the safety switches allow it to activate. So i'm just adding 1 relay and 1 activation switch and a power wire to the 2nd solenoid. Does this sound OK?
i'm also adding a purge, is a relay necessary for it?

 

You really want to get the FPSS off the high current side of the relay. They aren't made to handle that load. You can put it inline with your wot line. As for the 2nd stage, it sounds like you're fine but it would be better if you post up a schematic of how you intend to do it.

 

this is how i had it set up.
for some reason. the new stage(2) would spray for 2 seconds with key in run when the activation switch was "on" even though it didn't have the WOT switch pushed in nor the WS activated.
----if i had the car running, it would continuously spray even though the WOT switch was not pushed in nor the WS activated(at least it wasn't supposed to have been activated since it was idle rpm=600.

the relay is supposed to get its ground from WOT switch is which is supposed to get it's ground from the WS, but neither should have been grounded when the activation switch was in "on", so i'm not sure why it sprayed. stage 1 didn't spray when in the "on" position.

 

i think i found the problem. my 2nd stage was getting a ground from the 1st stage relay even though the 1st relay didn't have a ground coming to it, it was acting as a ground itself. how can i get around this?

 

my goal is to have to separate stages. i have an 80 on the 1st and a 50 on the 2nd. i want to be able to spray either one at a time or both together. so i have it set up as:

FPSS gives ground to WOT which gives ground to the msd 8956, which feeds a ground to both of my relays at the same time. then i choose which relay(s) i want activated by using the arming switch(es).
My concern is that going WOT and then giving a ground to the msd instantaneously might cause a problem in the msd's reaction to send out the ground to the relay. msd says it should be ok to instantaneously give a ground to the 8956 WS, but i want another opinion. anyone tried this setup before?

here's a new diagram.

 

Much better.