Fit guns, fit tank, fit speed mod. Not that hard for you to try yourself, really.

You expect us to do your work for you? Get out

e: If you'd at least suggested a fit in your OP, that would've gone down a lot better; as it stands, it just looks like you wanted to be spoonfed.

It will be pain in the ass to shoot frigates, especially when you have low/average turret skills (I assume you have)
so yeah, go for a cane

If you're going to take a Tornado into a L3 mission space, bring escorts in frigates and cruisers.

Seriously. One rat frigate webbing and/or scramming you will ruin your day, and even with the smallest autocannons and lots of tracking boosts, it's too easy for the rats to get under your guns if you get a close-range spawn. Never forget that you're basically flying a high-speed beer can. Okay, it's a beer can with a Maelstrom's broadside, so you can one-shot a rat battlecruiser if you've got the proper firing geometry and the right weapons, but god help you when those smaller ships get to close range.

Large Projectile Turret 4 does not mean it is more useful than Medium Projectile Turret 3 mate.

You have much more to learn

i once tried to get the tornado to work with one medium or small gun. iirc the best case scenario was that you would deal ~40dps to obiting figates which is half as much as a set of light drones. i never tried it myself though so feel free to go for it.

...unless you desperately wanted the ship to work in a situation it is not really suited for. see it like this: you sacrifice ~15% of the tornado's overabundant dps for the safety of being able to warp out at any given time.

You have so much to learn.

Bigger does NOT equal better, and in fact by doing level 3's the only thing large turrets will do is slow you down to a grinding halt.

L3's = close spawns
Small ships
fast ships
Enough damage to break a small tank

Guess what large guns fail with?
Guess what ship has a small tank?

Large guns will be able to deal with smaller ships, especially projectiles, but not at close range.

My maelstrom is over 1000 DPS, yet I wouldn't take it to a level 3 (sure, would tank it more than fine) I'd take, yup, you guessed it, a hurricane.