Some tips if you are planning on running the sub solo:

Make sure the ammunition is topped up, and all the guns are manned by bots and the ship can be left more or less unattended for quite a while.
Because of the size of the ship, I find its best to have two of each class minimum, except for captain.

2 mechanics for welding + any spare crewmen not commuted to continuous jobs can help out. You can also grab a third mechanic specifically for deconstruction allowing you to just mark things for decon and let the mechanic come grab them. (Even in vanilla barotrauma, this works best if the item you want deconstructed is in a container and not just dumped on the floor)

2 Engineers, one for monitoring the reactor to keep the ship running at full efficiency, the other for electrical work.

2-6 security, you can use assistants for the gunnery especially if their apprentice perks kick in right, and getting the tandem fire buffs from the security will help. Your security are primarily your gunners, let the cheap assistants take the risks with intruders.

2 medics, 1 will be your ships dedicated doctor, who's sole jobs are heal the crew and fight intruders (heal the crew first, as helping in the fights is secondary.) The second medic will be either your backup, or your diver. (You can get an assistant if short in funds, or a mechanic if you prefer faster mining) As this will let you collect alien genes and reliably heal yourself if in danger.

A second captain is optional but if you do take one, setting them on the guns with the sec and assistants can quickly build up their weapons skill.

Fill the rest of the crew with assistants who are set to fight intruders and weld, they are your real security. You can also set a few to cleanup items to make them keep the sub in order (I think all the container tags should be set up right for that)

This should automate most of the ship, though you will still need to manage deconstruction overflow, and of course, you will have to do the away missions yourself with your chosen diver. Feet first into hell!