At 60 tons, it's a medium, and medium pulses don't threshold anywhere. 
Your wings and aft will still get thresholded by (R,U,L)AC/5s, LRMs, ATMs, flak, any non-UAC cluster weapon from aerospace, and countless other non-DE sources of 5 damage or more (as well as DE sources dealing 9 damage or more). Laser-Reflective is
very nice in the laser-heavy realm of aerospace fighters, but relying too much on it can be a lethal mistake. Besides, once your opponent knows how much you depend on it, expect Long Tom Cannon fighters to start showing up; a single hit to your wings or aft will instantly ablate all the armor in those locations and start going structural, and even your nose can't take that sort of abuse more than once.
Also, you will be at 4 thrust if you bring your max bomb load (max of 12 bombs, 12 / 5 round up is 3, 7 safe thrust - 3 = 4 fully-laden safe thrust).
What do you mean by custom weapon? I don't see any quirks associated, and Snub-Nose PPCs already have their own established rules in canon, as I'm sure you know.
The weapons loadout is impressive, but if you don't mind my saying, this kind of looks like a classic case of trying to do everything badly. Okay, that's a little unfair, it'll do a lot of things well enough, especially against less maneuverable opponents trying to do the ol' reliable large laser spam Succession Wars approach. However, I feel like basically any other approach to aerospace force building will quickly highlight the weaknesses of this fighter. I also tend to be inherently skeptical of 7/11 fast dogfighters; that extra safe thrust comes in handy sometimes, but that's a lot of tonnage spent on a pretty situational advantage. Maybe that's just me though.
Anyways, tl;dr, it's a good shakeup option if you're playing with someone who's gotten stuck in the Succession Wars dogfighter meta, the cult of the large laser, but I feel that outside of that context many elements of the fighter become lackluster, and the whole thing ends up being worse than the sum of its BV.
(The moral of the story is the Dracs had it right all along and AC/10s and LRMs are actually really solid in aerospace regardless of era if you can build around them well.)