Shadowhawk was hands down my favourite mech with the ability to take punishment and do a decent job dealing it out while being fantastically mobile, but alas very poor quirks really hurt it when lined up against the best. When this sweet chassis landed for clans I was pretty excited, it took me a little while but this build is just the ultimate replacement for my shadowhawk, and exploits everything great about clan weapons - IMO its perfectly placed to be a powerhouse at 55tons. The Twin LBX10s are the main draw here, great firepower and excellent component destruction. Whats more, the top most left arm ballistics hardpoint is extraordinarily high for an arm mount on a humanoid mech - it sits on top of a gun assembly, which is attached on the top of the hand actuators. You should have very little trouble getting both shots over cover and have a very tight shot placement. The Twin SRM6s are to help along the alpha up close (and combined with skills for crit missile are another way to help get kills and components), I did try some builds with ARTY, however it just pushed the limits to much. The Twin Heavy Mediums are quite important, as its excellent damage, and while the range isn't great, its certainly not terrible and can use to poke a little. The main draw for them is that I found myself lacking firepower in when losing my left torso - by adding these in, I have a 64 point alpha, 32 points on either side. Having balanced damage delivery is good. Just the 1 JJ and a 280, which keeps you pretty mobile and helps get where you need to go - no pop tarting though. The quirks for JJs actually make this work almost like 2 in a normal mech. Ammo can be tight in long matches, but the heavy mlas help keep you in the game. Hope you like it, and have fun making your own variants!
I've had to make a few changes given the torso heat issues. Firing two heavy mediums while under the head reduction effect of a lost torso is just too much to handle. I guess keeping most of the build intact, you go with either 3 small heavy pulses + 1 more JJ (my choice) or 2 regular er mediums if you want the ranged poke (I've been using this a bit too and its fine). I think it depends on your style of play on which you might go.