I'm not sure about that preamp, but you got the mic right. Take a look here: http://www.hometheatershack.com/foru...ease-read.html
I use a Creative USB 0202 preamp. It really doesn't matter which one you use, but I think the tube preamp is likely a bad choice.
I would suggest using REW for measurements. You can also use HolmImpulse. They are both free and work well.
You will also need modelling software. Passive Crossover Designer is a free application that runs in MS Excel. It is a good beginner tool, IMO. Most other tools are much more expensive and complex.