I have been looking to find some reading material on why certain fabric weaves are used in certain applications, like why use a 2x2 vs a 4x4, why use certain sizes of spread tow in some applications, etc. 

Is there anywhere that I can start to get more info on material selection and the advantages/ disadvantages in situations?

Thanks!

Agree with both the comments above.

Worth baring in mind for most common hobbyist/diy applications is that the looser the weave, the easier it is to drape, so a good general rule of thumb is that a twill version of a plain weave at a set weight will drape fractionally easier, same with some satin/harness weaves in certain directions. UD's and Biaxials can be flatter, but their use depends on your application.  UD is not great for infusion due to no gaps, biaxial will mostly infuse but a bit slower than typical woven cloths. Spread tows are great for being flat, but as they are in effect wide strips of UD woven, sometimes with infusion you can get areas of voids, but this can be sorted by modifying your process.

I am sure there are plenty other rules of thumb people use.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant