I don't think it's worth it to be honest. Most of the tougher NPCs of the game feel like they're more hull than shield. My Python carries the following:
Top Large: C3 Gimballed Multicannon, G5 Overcharge, Auto-Loader
Top Large: C3 Gimballed Multicannon, G5 Overcharge, Auto-Loader
Bottom Large: C3 Gimballed Multicannon, G5 Overcharge, Corrosive Rounds
Medium 1: C2 Railgun, G1 Longrange, Feedback Cascade
Medium 2: C2 Railgun, G1 Longrange, Super Penetrator
The multicannons are just DPS hoses. Feedback Cascade denies target shield cell banks with good timing, and the super penetrator punches through to snipe Power Plants. IF you're struggling with heat, something's wrong - Overcharged does not increase the thermal load of your weapons (Incendiary Rounds do though); I'd suggest taking another look at your Power Plant.