Alter Self and size changes

[Lastoth]

If a human casts Alter Self and assumes the form of a Charu-Ka, would he get any other bonuses associated with being small like the +1 bonus to hit? Would his weapon die code drop also?

[Imbicatus]

Yes. If your size changes, any size based effect applies. You weapon size would drop, you would gain a +1 to hit and AC, and a -1 to CMB and CMD.

You would also gain a +2 to dex from the spell.