Enough ammo for any weapon system, and it should work quite well as exp grinder in PUGs while levelling solo. I would use a 4th Group for a TAG macro toggle for this mech.
http://www.mechspecs.com/forum/index.php?topic=7904.0 Sorry for being so lazy, but just had this one posted previously and i thought "WoW, exactly what i want to say again" Taking into account the intended role of ur build, i think i would refit it like this: TAG and cMLas in the same side (range is the same, so if TAG is working, ur cMLas will too), and a cERLLas to backup at extreme range, that giving the speed of the mech can be usefull.