running gas lines for secondary regulators and manifolds

[Nyakavt]

Caution on trying to connect your secondaries directly to the tank. I don't think you should do that if they truly are secondary regs. They can't handle the direct bottle pressure. Keep your primary and run off that.

This is true, I tried connecting a true secondary regulator in series with a primary regulator and it wasn't giving me any gas at the kegs. It didn't damage the reg, but since the spring rate/diaphragm was different inside it was not able to regulate.
After hooking up gas from the output of the primary into the secondary it worked fine. It sucks that the pressure must be less than or equal to the pressure from the primary, but that's the only way it works.

As for removing stuff from the secondary regs, did they use loctite red? If so, you're probably going to need to use heat to break down that adhesive, lubricants usually don't penetrate adhesive very well IME. You'll want to remove all of the internal parts of the regulator before applying the torch so you don't damage them. 1/4" pipe threads aren't that big though, so you can try to do it at room temp by clamping the part in a vice and using a big wrench on the hex.

[San_Diego_Matt]

I don't see any evidence of Loctite red on the reg, but they sure as shit aren't budging. I was able to get the gauges off them, but none of the rest of the stuff will break free.

I'll try the vice option and if that doesn't work, I'll strip them down and put the heat to them and see what happens.

Since I probably won't be able to connect these things directly to by CO2 bottle, I'm guessing I can unscrew the tank pressure gauge (the 0-2000psi one) from my primary regulator, screw one of the secondaries into where it was, the other secondary with the attachment arm shown above, into the first secondary and then the gauge into the left hand side of the 2nd secondary?

[Nyakavt]

Since I probably won't be able to connect these things directly to by CO2 bottle, I'm guessing I can unscrew the tank pressure gauge (the 0-2000psi one) from my primary regulator, screw one of the secondaries into where it was, the other secondary with the attachment arm shown above, into the first secondary and then the gauge into the left hand side of the 2nd secondary?

Yes that will work but only if they are primary regulators. Did they come with barbs on the 'in' ports? If so, you may not be able to connect in-line with your primary regulator (although you can connect them in-line with each other), like I said I tried that (Micromatic premium 'secondary' regulator) and it didn't work. I looked on the MM website and the secondary regulator had a different part number for the rebuilt kit than the primary (presumably different diaphragm or spring rate). It seemed like it worked at first, but I'd go back a few days later and the pressure would not adjust on the secondary reg. You also want to make sure you indeed have LH threads on both regulators, both of mine were, oddly enough, RH thread. If they are the same brand then they will most likely have the same thread on the high pressure ports, but it doesn't hurt to check. Last thing as I'm sure you know is to use teflon tape, the yellow stuff is thicker for gas applications and works great for CO2 regs.

[atomicpunk]

I agree. I don't think you can put them in series because that just passes the high pressure through the secondary regs. You could directly attach to the outlet end (bottom port) just not the side port which does not drop the bottle pressure.