Multi-armed Eidolon

[Blodox]

I'm building an eidolon and it has 2 sets of arms, and I'll be doing multiweapon fighting. I'm wondering if I have a main hand on each set or is it just 1 main hand and the other 3 are off-hands. I'm looking to do a Shiva-like build and have a different weapon in each hand.

[Rathendar]

1 main, 3 off.

[Alexander Druidus]

yeah 1 main and 3 off look at the maralith.

[David knott 242]

One problem you will face is the inability to duplicate the marilith's ability to make all of her weapons work as though they were enchanted. If you want a decent chance of hitting, each of those weapons would have to be enchanted separately.