Mose,
Here's a few points to get you going...
1. Congrats on your new purchases. I've had a VL for several years and it hasn't disappointed me. It takes some time to get used to, but all in all it's a trusty tool that is very versatile.
2. Pressure ratings really depend on the paint and it's consistency. If your paint is really thin, then you'll likely use a lower air pressure like 8-10 psi at the least. If it's thicker, you will likely use anywhere from 15-25 psi to get the paint out. In some cases, you may go even higher, but I haven't found alot of need for anything over 25 psi. If you're looking for a 'starting' pressure, try 15 and work around that.
3. I haven't used MM Acrylic paints, but you'd likely be better off to thin it rather than shoot it right from the bottle. I assume that alcohol will work, but perhaps other forum members have more experience with this paint. I think you'll find that paints will flow best through an airbrush if they're thinned to the consistency of skimmed milk (if you're in doubt, go buy some skim milk and put it in your airbrush jar/color cup to get an idea of the consistency. Dip a brush into the milk and watch how it runs off the brush. Take a toothpick and 'drag' it up the side of the color cup to see how it runs down the side of the cup. You'll get the idea pretty quick.)
4. When you clean the needle, be sure to clean the rest of the airbrush parts too. When I put it back together, I put the small brass 'cone' and it's matching piece onto the airbrush first. Then, I insert the needle. On my VL, there's a slight bit of resistance to the needle when it hits the 'seal'. Go slow and push the needle past the seal and slowly keep pushing it until it seats into the brass 'cone' that is already installed. I just nudge it up so it meets the cone and then tighten the screw at the back of the brush so the needle is locked in.
Hope that gives you a start. Just remember one thing. Using a tool like this is a bit more of an art than a science. A lot of the paint consistency and pressure stuff is more from experience and feel than anything else. Keep asking questions though, there's a lot of accomplished artists here willing to share what they've learned. As for myself, well I'm still learning too.
Enjoy your new set-up.
Murray