Light Repeater Gnome Artificer 20
Heavy Repeater Warforged Artificer 20
Heavy Repeater Halfling Artificer 13/Fighter 6/Rogue 1
Damage comparison
The four different modes are:
Epic - All boosts including epic moment
Full - All boosts except epic moment
Partial - Endless Fusillade
None - Just auto attacking
The damage summary does not reflect personal debuffs, like Fetters of Unreality on Stickerclick. So in a vacuum the heavy repeater comes out ahead damage-wise as you'd expect.
It might be a surprise to some, but Crusade is the highest damage epic strike when compared against Hunt's End and Shadowstrike.
The DCs with the light repeater build are consistent enough to land Prismatic Strike on bosses (-25% less damage done) which is vital to keeping tanks alive. It's a tactic we've used before in our high skull raid completions. Tactical Detonation and Overcooling on trash is super useful.