I am surprised that I did not find this build already posted, but there are 6 pages of builds, so I may have missed it. The design philosophy is dps/ton efficiency. AC2 has the highest dps/ton of all the ACs. UACs and RACs can get much higher, but are not as reliable over time. SRM2 has exceptionally high dps/ton. I need to check again, but I think that it is ranked #1 of all IS weapons. Cooldown quirk of -15% to all weapons is superb for this goal! The playstyle is very flexible. AC2s reach very far so you can be very active in the early game. However, I do not have the patience to play a sniper and almost always end up close - this is when the SRM2s kick in. The combination of 3AC2 and 3SRM2 pours such stream of damage, cockpit shake, and blinding flashes that few dare to stare you down if you started shooting first. The weapons do not jam and you do not overy-heat so use the decent speed and JJs to move around and keep shooting. These are not RACs - you can pop out of cover, unload a few quick volleys and duck again to come out of another angle. Alpha is 18 damage, but you get another 6 from the AC2’s 2nd volley in the same time as a pulse laser. 24 damage in 0.6 seconds (cooldown quirk) is nice. Very active and very fun build. Take all the ammo skills, you will need them.
My -2H currently just runs the 3xAC2. It's fun, but at some point the amount of DHS and ammo that are put in have almost no value. I think it's worth trying it out with 3xSRM2 as a better way to spend those tons My version runs an extra ton of AC2 ammo.