I was hoping someone could tell me what is the max. deflection angle that a stormdrain pipe can be lenght wise and also how long do they typically come in.
varies greatly, and depends on the type of pipe. Generally not more than a few degrees of deflection per joint. you should call a manufacturer of the particular type of pipe that you intend to use and get the answer from them.
You can buy bends for RCP. I think they are 7.5 degrees. if you start out deflecting joints you will not learn to layout storm drains properly. Use the bends.
If reinf. conc. pipe, the manufacturer can tell you how much deflection you can get with his pipe. A 24" RCP can be laid with a 140' radius. If you use radius pipe, it may be as small as a 65' radius. If you use a "pulled" radius pipe, 40'
Get a catalog from Hanson pipe. It has all the info.
You can always cut RC pipes and put two ends together using a concrete pipe collar. Typically I do not exceed 45 degrees when doing this. As long as your increased head loss does not blow out your system's hydraulics, it should be fine.