I am a well known pvp frag specialist, for what that's worth. I run most of my ships as 'shotgun snipers', frag and rail, though recently I've been swapping railguns on some ships for modded GPCs, it's still a shotgun sniper.
The method being to joust close to land frags, then hold boost and drift out, fire a few railgun volleys, cancel any cells, shoot any modules if the shield is down, then line up for another pass. This is incredibly effective in pvp, and useful in pve when outnumbered (remember you only need to outrange NPC weapons by 1.5km to reduce their damage to almost zero), so good jousting is a very important technique to 'git gud' at, as it provides exceptional offense and defense simultaneously.
If I address everything everyone else has said, that would add a lot of words, so I'll just give you my opinion in isolation.
First, choose the right ship and hardpoints. Whether a ship is well suited to gimballed frags, or pacifiers, is a fairly simple formula. If the ship has sufficient hardpoints that are on the upper deck of the fuselage (top mounted weapons), then it's ALWAYS gimballed frags. If the hardpoints are underneath or on the side (and therefore unsuitable for gimbals), then pacifiers are the better choice. Combat ships that support a gimballed frag build are the following, with their rating for using gimballed frags:
Mamba - 10/10 - every hardpoint is top mounted, Mambas are frag beasts.
Python mk2 - 9.5/10 - Every hardpoint except one is top mounted, and that lower nose hardpoint actually has enough separation from the ship, and the nose has enough of an upswept angle to make it a rare suitable slot for a gimballed frag. It will fire along with the upper frags as long as the enemy is in the bottom two thirds of the screen.
Python mk1 - 9/10 - All hardpoints except one are top mounted. It's a little frustrating to have a large underneath, but 2 large and 2 medium gimballed frags is devastating anyway, whatever else you decide to put in the belly hardpoint.
Krait Mk2 - 9/10 - 3 large hardpoints on top and the best railgun position in the game, attached to your pilot's ears.
Chieftain/Challenger, 9 and 8.5/10 respectively. The large and small hardpoints are on top and the lower(s) is/are good for rails. My challenger is a famous organic FDL killer with 4 frags and 3 rails.
Honorable mentions: Mandalay (4 out of 6 on top), and Krait Phantom.
Anywhere you have a large hardpoint that is NOT on top of the ship (exception - the belly hardpoint in both pythons), then Pacifiers are the better choice. Why are gimballed frags better in up facing hardpoints? Simple, while Pacifiers do have more speed, making landing a shot technically easier, and a tighter spread, allowing more damage from a longer distance, this is ENTIRELY offset by the fact that it is near impossible in the heat of a turning battle to land all 3 volleys clean and centered on the enemy. Gimballed frags on the other hand do more overall damage, and almost always put all three shots center mass as long as your ship position is correct. Some might shout 'skill issue!' which is fair, but why make your life more difficult and be less effective, just because someone says the other thing takes more skill to use? Sorry, I'm about effectiveness, if you want a demonstration of my skill, hang on, I'll be back in a few with my FDL. Lastly, having to line up pacifiers carefully and STAY lined up for the duration of the volley makes you really easy to hit. You can boost and spiral around your target and still land all three shots from gimballed frags.
So, trust me, if you want to dominate a Pacifier using Py2, simply mount 4 large gimballed frags, ignoring the no gimbals in belly rule, because that hardpoint is special, like me

. Put your preferred mid/long range weapon in the two medium slots (or more frags if you're insane

). Don't bother with Pacifiers on any of the ships in that short list above. Hope this helps. Feel free to review my youtube channel for multiple demonstrations (The Ashen Fox)
I could talk about frag/rail theory all day if you want to know more, fire away. <3
PS. gimballed frags fired at the right range and the right angle, also dgaf about chaff. 60% of the damage still lands.