I run this build on my Firebrand with one less AMS and one extra heatsink. Figured I'd give it a shot with the 9S...it's working pretty well so far, despite not even being basic'd.
too bad you've got way bigger side torsos for the XL and you don't have the high ballistic arm mounts. Odd that I didn't even think of this build when building - I'm too enamored with the high energy RT mounts to waste them on MLs.
I haven't had too much trouble with the TDR's side torsos getting blown out. The CT is plenty big enough to attract attention, and the arms soak up a surprising amount of fire directed at the RT/LT. On the MLas front, there's no shame in stuffing 4~6 of them on a 'mech. They're an effective weapon ... especially because everyone seems to write them off.
MLs are great because of their balance of tonnage, slot, and heat, combined with capable firepower. They are best when used on a small-to-medium scale with other weapons, or boated to the nth degree. This might not have the high mount of the Jagermech, but it will be easier to hit things in the brawl. I am currently trying an ERPPC + SPL build on my 9S, but I like the looks of this as well and will have to give it a shot.