Purpose of a catch can is to contain fluid overflow from 3 areas: Coolant, Fuel and Crankcase. It's not practical to make one can large enough to contain all 3 substances, so you'll need one for each. If your crankcase breather hose runs into the airbox(which is common)you won't need one there. Red Bull cans, Coke cans, Budweiser cans etc are old school and quickly becoming unacceptable with most sanctioning bodies. When considering a catch can, 3 things should be foremost;
-Able to withstand a substantial impact
-Large enough and able to contain all of it's contents in the event of a crash
-Be heat resistant
If at all possible, mount the can in a location that would reduce or eliminate it's exposure to damage.
SM sanctioning bodies have realized they face the same issues regarding catch cans as Roadracing outfits do. Show up for a race with a GSXR 1000 using a red bull can and they'll laugh at you and tell you to come back when you're serious. If you can fab a quality can at home, great. Most can't. For less than $100 you can purchase all 3 catch cans(coolant,fuel,crankcase) from a quality manufacturer and never have to worry about passing tech or spilling crap on the track.