Can you over-base the mixture? i understand too little wont lower the pH enough, but will too much affect yield?

it won't affect yield so much as waste lye.

if you follow the tek precisely, you need not worry about the PH.

we have done the worrying for you.

also, i believe you can safely go as high as 1:1, but even with dry tek there is no need for that (using lye)

Not with NaOH. Though, as always, take extra caution with a lower pH solution. That is, gloves, mask, eye protection, etc. The lower the pH (or higher) the more dangerous it is to work with... but usually better yield since the material will be fully broken apart.

Don't forget to add pH strips or a pH meter to the wish list.

Okay thank you! My scale broke so I just eyeballed it. Ill have to ask summer santa for a new scale and some pH strips. thanks again!

I found that a digital ph meter works wonders for precise readings as long as its calibrated correctly.

presuming you over base and the solvent comes out a dark dark colour there is an easy way to fix this.

take some water, saturate it with salt and add a tiny bit of something acidic (like a teaspoon of vinegar or citric acid).

pour the saturated acidic water inside the jar then shake the jar, it will collect almost all of the lye then you can just decant.

from there proceed as normal.

A good pH-lye read:
Easy NaOH alternative tek / Sodium carbonate tek