I've played alot with outfits on the python. For pve, I go with 3 Gimballed Large Pulse and 2x Multi canons also gimballed. That's pretty standard.
I switch it up sometimes and put in 2 medium turrets in the medium hardpoints in place of the cannons. This helps with pesky, low armor targets such as nimble fighters, vipers, eagles, couriers, whatever.
I know that beam lasers strip shields faster, but the power drain, rate of drain on the capacitor outweighs that for me. Because once you're into the NPC's hull if they are heavily armored, beams suck, you'll find yourself draining a full capacitor, only for 10% damage maybe on a large target, then having to wait for recharge, rinse repeat, all while getting hammered. This means more scb use for you or chaff. While the pulse arent as good against shields as you see in the chart and as we know, when it gets to the hull, it outweights the disadvantage of their lesser shield stripping capability, it really burns through the hull.
For PVP, its beams all the way. The faster you strip people's shields they tend to bug out, and this puts less guns on the field for your enemy. Spike damage or alpha striking is better for pvp, and you and 2-3 of your mates in pythos or whatever, can strip shields together fast carrying 3 beams each, no need to worry about power drain here. You've got 12 large beams stripping a target.
And 12 beams will strip any hull anyway. But like I said, people tend to be like, oh noes time to retract and go when the shields are going down. And the pulse just wont be equal to the task when your in group pvp. Whether you use fixed/gimballed for PVP is up to you. But again in groups, having both is ideal, use the fixed when their chaff is on, and the gimballed when its off.