Can you install them in something big like a Corellian Corvette?

I don’t recall any size or class limitations on those droid brains. So, my opinion would be to say “why not?”

But you should probably ask your GM that question. They might have different ideas.

Aye, one thing to remember is that the star wars universe is fairly anti-droid in policy, thus the idea of having an astromech mind installed on large ships would probably give the ship a very iffy reputation. The katana fleet being an extreme example of what happens if droids are allowed to do more then routine tasks. It's part of the reason that crews of captial ships tend to be so huge; everything is manually operated from very exact computer terminals with very few automated stations. Hence it isn't so correct to say a pilot is flying a ship, but rather he's sending orders down to the engineer's to adjust headings. Least that was my impression of a ship like a star destroyer and was discussed in one of the Trawn books (which discussed that these ships could have a comparatively small crew, because so many of it's systems were automated. Yes I know it's non-canon, but there are a very few sources on how a ship works so it really can go either way.)

Basically, it could work, just it isn't a very common job due to droid mistrust.

No reason not to, apart from Lordbiscuit's points.
Interestingly I read about a real world comparison, just launching into our seas.

Can you install them in something big like a Corellian Corvette?

I recall reading somewhere that the Falcon had both types of Droid brains. But they would argue against each other, causing problems. That's why Han had C3PO talk to the Falcon in Ep 5.

i would allow it, but a corvette is way bigger than a small freighter, and need way more crew to fly. A droid brain has a limited computing capacity and so : if 5 people are needed to pilote a corvette (one is holding the stick while the others are tracking engine behaviour/gravitics adjustments/whatever), i'd require a droid brain cluster equivalent to 5 droid brains to do so.

Same for Astrogation, a massive spacecraft probably require way more complexe calculation than a small freighter.

So i'd, i think, require 1 droid brain per crew member replaced, with maybe a 30% price discount overall for the redundant software.

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and you should fear the ion damages

Conversely, maybe you can’t get a droid brain cluster to cover all those areas.

So, maybe the droid brains that can be installed on a larger ship might only cover some of the skill areas on that type of a ship, and not be able to provide skilled assistance for all types of skill checks — those parts still have to be done in a more manual fashion.

Again, I think it’s up to the GM, and it would be good to have a deeper discussion with the players on this topic.