At 8 RC, you're at Long Burst / Short Burst without recoil penalties. Only a Full-Auto on both comes at -1x2=-2 Recoil on each arm when firing simultaneous.
Of course the question is how well a drone handles firing simultaneous when operating by itself or when being controlled. Controlled would clearly be splitting your dicepool, autonomous I'm not sure. What's to prevent you from running the Pilot and Targetting programs twice on a Response 6 drone, using each pilot and targetting for 1 gun? Had a thread on it on the
SRU site, but no clear answer came out of that.