
KA-BOOM! |

Okay, I've just about finished my character rebuild and have decided to ditch the White-Haired Witch part of the idea and stick with 4-8 ranks of Musket Master and 12-16 ranks of Grenadier. Now I will be taking both spare arms and the tentacle from the Alchemist Discovery list so I will have four arms and a squiggly thing. Four arms means i can physically carry two two-handed weapons. What I want to know is how does this effect combat and my build? I already know I can't use the default Rapid Reload feat that comes with the class as it is explicitly for muskets, so there goes my first feat... How exactly does Multiweapon Fighting work? The wording confuses me and could either mean first attack is at a -2 and the second at a -6 or that both are at a -4. And how does Multiweapon fighting stack with high BAB and Rapid Shot?

Eridan |

-4 / -4
Multiweapon Fighting replaces TWF and it reduces the penalties (normal -6/-10, penalties reduced by 2/6 results in -4/-4)
With BAB +6/+1 you have 3 attacks with +2/+2/-3
With rapid shot you have 4 attacks with 0/0/0/-5
I see some problems regarding reload, culverine support and social competence but that was not part of your question.

KA-BOOM! |

-4 / -4
Multiweapon Fighting replaces TWF and it reduces the penalties (normal -6/-10, penalties reduced by 2/6 results in -4/-4)
With BAB +6/+1 you have 3 attacks with +2/+2/-3
With rapid shot you have 4 attacks with 0/0/0/-5I see some problems regarding reload, culverine support and social competence but that was not part of your question.
Reloading has been solved via the musket master and either a secondary feat or retraining of the Rapid Reload feat the character starts with depending on the GM. This reduces the reload from full round to standard. At level 3 the Musket Master gets Fast Musket which despite the name applies to all two handed firearms and allows me to treat the two handed culverine as a one handed weapon for purposes of reloading making it a move action... Alchemical cartridges make that a FREE Action.
I'm a little confused as to how BAB, rapid shot, MWF all line up mathematically. If I make a plane BAB attack its +6/+1, if I make a MWF attack it's -4/-4. So I can see how 6-4=2 and 1-4=-3, and I assume what you do is simply make the first two attacks at the highest bonus, right? Rapid shot gives me another attack but all of them at -2, following the rule of adding extra attacks to the highest bonus we get 0/0/0/-5, correct?
So what on earth happens with Improved Two-weapon fighting and Greater Two Weapon fighting?
With MWF, ITWP, GTWF, and RS that would be 0/0/0/-5/-7/-12? With a 2d8 30ft (60 with Distance enchantment?) cone and Clustered Shots?
Also, my charisma is an 18... or is that not what you meant?

Eridan |

For GTWF you need a BAB of +11 so i use this for my example.
Full attack:
+11 / +6 / +1
With MWF/TWF you get an additional offhand attack with your highest BAB and all attacks have a -4 penalty (mainhand and offhand)
Mainhand : +7 / +2 /-3
Offhand: +7
With ITWF you get an additional offhand attack with -5
Mainhand : +7 / +2 /-3
Offhand: +7 / +2
With GTWF you get a third offhand attack with -10
Mainhand : +7 / +2 /-3
Offhand: +7 / +2 /-3
With rapid shot you get an additional attack with your highest BAB and all attacks suffer a -2 penalty.
Mainhand : +5 / +0 /-5
Offhand: +5 / +0 /-5
Rapid shot attack: +5
Regarding social competence .. you have 4 arms and a tail !?! :)

KA-BOOM! |

Okay, now i get it... And the GM's let me re-fluff it as my character's tails because I'm a kitsune who isn't taking the tail specific feats or parasitic twin discovery and if a tentacle is dexterous to use a weapon as well as a hand, there's no reason to differentiate between the tentacles, arms, and "tails."
That's a LOT of damage...

KA-BOOM! |

Assuming you hit of course.
The more I look at it the more I'm considering a full 12 of Gunslinger... Between the BAB and the fact I'm hitting touch attack with a weapon that ignores most of the usual environmental issues I don't think I'll have a problem. I will need to be prone most of the time but I can work with that. Snap Shot, fast crawl, and prone shooter.