If you are planning on guiding with a second person on that 10’, I hope you’re both small, aren’t motorizing it and don’t have alot of equip.
With a max weight of 500#-62 for hull that only leaves 438 for 2 adults plus all the gear.
Self bailing capacity starts at 350 and drops from there.
No I don't plan on guiding in the kayak with another person . I have 2 extra sot kayaks I could use but most fishermen have their own kayak that they would rather fish from anyway .
Fishing can be anything you want it to be
All else in the hull design being equal, longer is faster and shorter is more maneuverable. I would go with 12' unless you have some special requirement. It will still be pretty maneuverable.