How many credits for a small bounty and how much for a large one?

That will be subjective and story driven in my opinion. Use your judgment based on the difficulty of the target and then just slap down number you're comfortable with.

The Bounty Hunter's Handbook lists the lower end of planetary bounties at around 3,000 credits while the galaxy's most wanted typically start at 200,000. Absent any news about a bounty hunter sourcebook, I find this little guide excellent.

Presumably the Bounty Hunter career book will include some of this info.

The most expensive, non-Hutt, personal armor in the game costs 9,000c.

The most expensive Ranged-Heavy weapon in the game costs 5,000c.

How much of the "best" do you want them to be able to afford after your bounty mission and splitting the payout?

As as you want, because those are restricted items and thus are likely to actually cost much more then it states in the rule book.

Plus even then, walking around with overly expensive gear or gigantic weapons on ones person is likely to draw the law.

Lol... "restricted" he says.

I mean they are, but still. Stay off the Imperial Worlds, and if thugs are looking at you funny on a crime world, they're fair game.

Boba Fett didn't mind chilling at Jabba's place with his restricted gear. My players have worked towards that.

A bounty in my play-style depends on what you or the chars in question have done.

Bail jumping, minor infractions, theft, ... yeah, 3k seem reasonable.

Murder spree that get screentime in the news? Up we go into the 5-digit-numbers.

Piracy, all-out terrorism and sabotage of military installations? Welp, you are now looking at a minimum of 200k Credits. The more damage you caused the higher it will go.

A heavy transport with over 400 tons of goods can be ransomed by pirates for a minimum of 100k for the ship, cargo and crew. What is cheaper? Repeaditly paying the pirates or once paying a Bounty Hunter (group) a sum that equals several randsoms, but stops those pirates and sends a signal to the others?

Considering what a BH risks in order to get his prey and what equipment he needs those bountys to be high. Otherwise you'll only attract ... mediocre employees.

Lol... "restricted" he says.

I mean they are, but still. Stay off the Imperial Worlds, and if thugs are looking at you funny on a crime world, they're fair game.

Boba Fett didn't mind chilling at Jabba's place with his restricted gear. My players have worked towards that.

Boba fett was also an exceedingly famous bounty hunter and wasn't walking around with a 5k auto fire blaster rifle. Aside from the flame thrower there wasn't anything that one couldn't get legally, admit heavily modified (well, and the single shot missle.). So really boba was the exception precisely because of reputation. Certainly an admiral goal for PCs.

As said though it depends where the party frequent and campiagn vibes. I imagine the big ticket bounties would also be exceedingly dangerous individuals.