tl;dr: combination of weapons against a NON-engineered but well-equipped and A-rated Anaconda standing still as a target and waiting to be shot down. 2x2B Railguns & 2x3C Cannons to finish in 1-2 mins.
Tests against an
2 x 2B Railguns & 2 x 3C Cannons remove shields 00:36, armour: 00:23
notes: 4.0 pips to STOCK WEP for 04:27, 3.0 pips to ENGeD WEP for NEVER. The combination of railguns and plasmas is too taxing even for the 7A engineered distributor and the inclusion of fragment cannons adds complexity to an already complicated situation.
2 x 2B Railguns & 2 x 3C Fragment Cannons (5° jitter) remove shields: 00:33, armour: 00:24
notes: 3.0 pips to ENGeD WEP for NEVER. Railgun's speed is 850 m/s and cannon's 800 m/s.
5A STOCK distributor (Vulture): 1 x 2B Railgun & 1 x 3C Cannon shields: 01:07, armour: 00:48
notes: 3.0 pips to STOCK WEP for NEVER. Heatsinks maybe needed for prolonged railgun fire, also 3 pips to WEP will degrade ship's agility. Note that the Anaconda can afford to have several turrets on top and bottom and can hit you all the time. The above figures are the best case and blue sky scenario.