I also got my custom tags through GalronMFG and same with the last of the green enlisted rank pins I needed. They do a bang up job on the tags. Highly recommended!
ScifiHero is also a good source of information on the uniform construction. Blues and greys have to be done from scratch. The green and tan BDUs can be purchased and easily modified. Any standard olive drab green will work for the regular uniforms. As for the tans the show used Law Pro for those. One of The Colonial Fleet members acquired a set from the Propworx auction and took pics on how things were sewn up. Very simplistic really. The tans do use different buckles for the pockets compared to the greens.
For your tanktops a lot of us are going through http://www.anovos.com
. They're pretty good replicas.
I can't say much on the flight suits other than the Sommers material is very expensive. I do the deck crew coveralls and BDU uniforms primarily.