The gauntlets give size-appropriate javelins, right? So I'd say a race with powerful build (or better, the strong arm bracers) are a good option.
Tormtor School is really cool. I'd just worry...doesn't the ranged attack still provoke? Spells have that handy little note that swift ones don't provoke. Ranged attacks aren't so fortunate...
Not seeing the appeal of Scorpion Heritor, it looks like a terrible class and the level 5 ability is weak poison and only 3/day.
Since this is a throwing build, Master Thrower is a great choice, as always. Trip Shot is good, and the Weak Spot is amazing with Power Throw. Bloodstorm Blade 4 is also great as always, but kind of invalidates the whole point of using the endless javelins.
It's a shame D&D's always been so allergic to items or class features that just plain imbue every attack you make with an enhancement bonus, aside from Vow of Poverty. I made a custom item for that, but that's probably not helpful to the OP.
EDIT: I think dipping Hit and Run Fighter for dex to damage on flatfooted foes, then dipping a sneak attacking class (best option: Swordsage to acquire Assassin's Stance, but rogue works) for sneak attack so you can get Craven is important. To help with the damage problem.