Hastened Deflection(+Shield Recharge) for better shield-gating invulnerability.
Shield-gating grants invulnerability when shield is broken. The duration of invulnerability scales from 0.3 to 1 second depending on how much shield was left when it was broken.

[Tek Enhance] provides longer [Charm] buffs.

[Synth Fiber] adds some nice passive reload of weapons, and lets you pick up health orbs at max health, which has some synergies with Health Conversion and Equilibrium.

Check out my other builds on my profile. Especially the "Generic" build series, which show the optimal builds for 90+% of weapons of that type.