When you create an eidolon in Pathfinder, it gets evolutions including limbs and such over time. But if you have a specific form in mind for your eidolon and would prefer it to not change so much visually over time, how can you make that happen?
For example, I am creating a serpentine eidolon that I would like to resemble a Lamia Matriarch ultimately. As such, I would like it to have arms and fight with a martial weapon (scimitar probably).
I'm pretty sure this is impossible straight from level 1: Limbs 2pts, Martial Weapons 4pts, and I have only 3 to spend. I was thinking I could use the one Feat to give Martial proficiency in Scimitars, but then it would be stuck with using that specific weapon type only or until I do pay for the weapon evolution... but then I've wasted a feat.
So I'm thinking I can wait until level 2 where I could spend my 4 points on Limbs and Simple Weapon Proficiency and have it use some staff or mace until it learns to use something better.
My problem is what to do for now: buy the Limbs and keep 1 point? What could it do with the limbs since it has no Slam and cannot use any weapon properly? Maybe I can still have it use weapons with the non-proficiency penalty...? Seems inefficient. What if I don't buy the limbs yet? Could I skin it as it having vestigial arms too weak to hold anything? I somehow don't think "no arms" will work for me; I want it to look like the lamia throughout its development.