Ships & Modules

Omnitanks are for PvP, sleepers, and incursions.

For missions, it just makes much more sense to fit a rat-specific tank. You will get a much stronger tank at the expense of fewer slots - slots that can then be used for modules that, e.g., increase damage, allowing you to mission faster, and make more money.

Edit: Realized you might be confused about Sanshas, here. Non-incursion Sansha ships, like the ones found in missions, do not do omni damage. They do EM and thermal. There might be a few RARE exceptions to this, but generally speaking, tank for EM/thermal for sansha and you'll be fine.

Anti-Sansha fits for missions is less about tank and more about being able to apply dps without worrying about TD. Missiles and drones would work which makes the new geddon kind of the anti-sansha ship once Odyssey drops, but since you mention Gallente ships, look into the Domi.

^^ as above. You can make a 'lazy rattlesnake' if you really want to that has omni resists if you just can't be bothered to change modules between missions, it still tanks more than enough.

In my experience omni-tanks are discouraged because they require expensive modules to pull off well, and you could probably fit an extra offensive module or two if you did a rat specific tank.

For example, if you want to omni a shield tank you are generally looking at using an expensive gist armor booster and a pair of caldari navy invulnerability fields, which can easily break 1.5 bil. Many shield tanking ships also have a large em hole, and you could normally be fitting an extra tracking computer in that slot if you weren't trying to close an em hole that will only be hit by a few rat types.

That's pretty much the reason why rat specific hardener setups are used. You keep the cost down by using meta 2 mods, while keeping equal or better performance. It also keeps you from being a lootpinata that gankers love to target.

Rattlesnake is the only ship worth omni tanking for L4's.

If you spend big and fit correctly it can have omni tank / max dps / MWD and plenty of other goodies.

The cheap version is the lazy rattle snake. Expensive version omni is just what is called a proper RS fit.

A Domi especially the new odyssey Domi may be a better choice for Sansha as drones are less affected by Tracking disruption and can do EM and Thermal Damage types.

Regarding omni armour fits the reactive armour hardener although cap intensive can provide a similar result as it adapts to damage. It is especially useful in missions with deferent rat types such as the dread pirate scarlet.

If they have reasonably thought out a plan to gank mission runners, they will use what they suspect you are not tanked against, damage that the mission rats aren't using, at least if they are multispeced, if they are single speced things get more limited, Hence people PVEing will generally loose in a PVP fight, poor setup and poor group comp.