So, after d!cking around with this for well over a year, I FINALLY have the brushless vacuum pump setup all installed in the car and working. The new brushless motor itself is a huge step up over the old brushed motor. It screams at full speed. It pulled -7.5 inHg on my test bench, which is twice the vacuum that the old brushed motor could pull. I think it may actually be able to keep up with higher boost levels (and the resultant increase in blow-by) that the old brushed motor simply couldn't handle. If it doesn't, I have a backup plan. So, we'll see...
I mounted my 2 relays, my Electronic Speed Controller, a 50 amp breaker, and my hacked servo tester to a scrap piece of aluminum and mounted the whole thing to the side of the trunk just above my battery box.
One relay controls main power to the ESC and servo tester. The other relay simply closes a connection that forces the servo tester to speed the motor up to whatever speed I specify. The speed can be changed using a 1/4 watt resistor that can be swapped out.
The whole thing is programmed to activate whenever intake manifold pressure is above -2 inHg and the vacuum in the tank is BELOW -4 inHg. Once activated, it pulls a solid -7 inHg and stays on until either the intake manifold vacuum drops below -2" inHg, or the vacuum in the vacuum tank gets below -8 inHg.
To sum it up.... anytime the intake manifold is under boost and the vacuum tank is below -4 inHg, the pump will be active, ensuring that there is constant vacuum in the tank (and the crankcase). And this will hopefully keep my dipstick from blowing out on long 4th and 5th gear pulls.
So far, the vacuum pump doesn't seem to hit the electrical system too hard on activation, which is good. And voltage only dropped like 0.1-0.2 volts while it was running. I was kind of worried it was going to be more of an electrical drain than what it it is.
Pictures:



In addition to the pump, I installed an additional one way check valve going to the vacuum pump with a junction pipe connecting the two outputs together. This is because I realized that there was a good chance that using only one valve was limiting how fast I could pull air out of the tank. The check valves open at a very low cracking pressure, like .5 psi, but they don't seem to flow a lot of air once open. Hopefully the combination of the brushless pump as well as the additional valve will fix this and I can refocus on tuning this b!tch on speed density!
Here's the additional one-way valve installed with the junction pipe connecting the two together:

