ORIGINAL: shd3920
QUESTION: How does one determine how much throw ailerons should have on a plane that originally did not have ailerons?
Set high and low rates based on a similar wing.
Throw determination is set by the aircraft designer which is you. Fly it and see.
Your build will be fine with high rates and high throw.
ORIGINAL: shd3920
QUESTION: Will the throws change on a stab that is made 10% bigger?
Don't worry about it, it's inconsequential. More stability equates to more latitude on other control surfaces, it doesn't matter IMO.