Any Tips on Engineer build? especially for the krogan ( Gold difficulty )

Dunno, im pretty often got top score as kroengi on gold vs outlaw and remnants. The trick is to prime with ammo then detonate with charged overload then detonate (because overload prime for 2-3 secs) with incinerate (6a evo). So 2 tech combos in short amount of time and target is still primed because of incinerate dot. Ofc u need a decent weapon too - i'm using raptor X and hurricane I.