portable A/c users, how do you have it set up?

ok, I think I have it all dialed in. I have my 18" fan on low blowing across the under side of the cool tube. 3-5" clip type fans clipped to the post blowing air up to keep air moving, an 8" 420cfm intake fan at 80%, an 8" 420cfm at 100%. the a/c feeds the tent thru the intake fan. I have the exhaust ran out with the help of another 6" 440cfm fan at 100% on a timer. both the a/c unit and exhaust fan are one a titan Apollo 8 timer. same timer I use in both tents. works great. fan speed is on low for the entire time the lights are on. it comes on 15 mins before lights on and 15 mins after lights out. temps are steady at 75*. im extremely happy with that number, and im sure the girls will love a 4* drop in temps.

did it help any with humidity levels?

no. im still running 50-52% r/h. 52 was max in 24hrs and 48 was min. im out of available power to run any more high powered electronics such as a dehumidifier.

50% RH is perfect conditions dude. even for flowering its good, so don't worry.

I port my portable ac heat into my crawl space under my house and vent the crawlspace with a centrifugal fan

I use a 16,000 btu a/c unit for the setup I have currently. The grow room is in a basement without easy access to a window for ventalation. I decided to duct the a/c exhaust about 20' to the rear of the basement and out a standard 4" drier vent. I used 6" insulated venting from the a/c unit and then put a 6" inline fan near the end of the ducting just before it gets reduced to 4" to boost the exhaust. The hoods are vented seperately with a 8" vortex fan and 900cfm carbon filter, and the intake is supplied by another 8" vortex through a industrial hepa filter.