As a rule of thumb the only time to load 800s for a battleship fit is if you want ‘long-term’ endurance for running point+prop(+possibly guns) for the super-rare kiting battleship.
Other than that Navy 3200s are generally superior. There’s been one or two people who’ve told me that Navy 800s can be better for cycling reps under neut pressure but I’m somewhat of the opinion that if you’re taking enough neut pressure to nuke 3200 GJ of cap fast enough that you can’t burn most of it on cycling your own mods then 800s are probably going to be about as useful as 3200s- that is, not very.
To put in perspective, if you want to use 800s for a dual-rep Hyperion you’re probably going to be locked into a dual-injector fit; with Navy 3200s you can run a single injector to fuel your dual reps and still have ample cap to run a heavy neut on top of the reps+guns+tackle.
First off, fit an MJD to a brawling battleship. Always, every single 100% of the time, fit an MJD. Being able to moonwalk out of long points (particularly against, say, carriers or just point kiters in general) is absolutely amazing and TBH is totally critical to an effective probably-solo brawling battleship.
An MJD forces opponents to move in close in order to keep you on grid, which is important because brawling battleships are terribly slow and can really only chase each other or unpropped ships down with anything resembling success, even if you have an MWD. So yeah use a mid for an MJD.
Secondly, as a general rule of thumb for the brawling battleship, you want at least 3 of the following tools for dealing with frigates and destroyers:
- heavy neut
- some additional form of application, like a tracking bonus, guidance computer, target painter, or web
- light drones
(most battleships don’t have the highs to pack both a heavy neut and a smartbomb, and generally the heavy neut will be better 99% of the time; a Marauder like the Kronos however has utility highs for days so a heavy+medium neut and smartbomb alongside Bastion and a full rack of guns (4, in the case of the Marauders) is totally doable)
For example a Hyperion that I have killed several frigates in has a scram+grapple+web and a heavy neut, as well as some light drones in the bay (note that grapple+web does allow heavies to apply to lots of things you wouldn’t expect them to, but that’s only if you’re right on top of something due to grapple range). A buffer Megathron would run grapple+web and light drones, and combine it with a tracking bonus (I’ve heard dual web also works since the tracking bonus means better hits and thus better applied DPS if you have something at heated web range but IMO that just means said something can run away since it isn’t likely to be scrammed).
For a torpedo-fit Typhoon you’d run scram+grapple+painter+missile computer, and optionally use a rig slot for a Rigor Catalyst rig for even more application (torpedo Phoon does however lose a lot of tank to get that Rigor on, since the CPU squeezes tight and requires one of the two plates to be compact as well as a compact DCU, while ditching the Rigor for a third Trimark means both plates can be T2 and as can the DCU; this actually accounts for something like a 10-15 thousand EHP difference too).
As an addendum never fit a Grappler to the Vindicator; with its web effectiveness bonus it basically has a super-Grappler since the grapples have an 85% velocity reduction in their optimal range (1 km cold, 4 km heated), reducing the further you go into falloff, while the Vindicator with MinBattleship 4 has 84% velocity reduction on a T2 web, from 0-10 km cold and 0-13 km heated. So for a Vindi run dual web instead of grapple+web.
Anyway dealing with frigates and destroyers at close range in a battleship isn’t hugely difficult if you fit for it, despite what lots of people would think.
Oh, for non-Marauder turret battleships, also use Keep At Range or Approach to minimize transversal; in a battleship you’re not going to be able to mitigate damage by maneuvering around- it’s just too slow and too fat to do so. That’s why you fit to have 115-120k EHP buffer or a 1500-2000 DPS active tank. By using KaR and Approach you can try and minimize the effective tracking your guns require to land good-quality hits on target, and thus have good applied DPS (note that you don’t need very many good quality hits against most frigates- double 400mm plate Punishers excepted- since you can easily volley through shield/armor; it’s just getting those few hits can be a little tricky).