Through Animal domain I've got a Mantis Companion (Level 8) and the Beast Shape III spell that through Share Spell I'll use to make him an Allosaurus (for damage w/o losing reach).
First...
Large needs to become Medium as base, per the Polymorph general rules
-4 str, -2 con (unsure why this, but it's RAW), +2 Dex
I assume at this point I also recalculate the Atk/Ac/Cmb/Cmd/etc +/- for size
+1/+1/-1/-1 respectively
Now with it's new Medium "base"
I apply the spell
+6 Str, -4 Dex, +6NatAr
Then, apply/recalculate the size based bonuses, now Huge
-2/-2/+2/+2 respectively
And lose it's old abilities for Low Light, scent, grab, pounce, rake, new move speed, new attack methods, reach/space, etc
Do I have the right of that?
[2nd question to herolab users... is there a way to get it to do all that automatically?]
[Bump]
At this point I'm 90% sure I've been doing it right if no one said anything, but still hoping for confirmation of the eclectic combo.