Basically I have a player that's interested in crafting magic items, and we use the dynamic magic item creation system from Pathfinder Unchained. He asked if there was any way to influence the results of the rolls for perks or quirks, and I honestly have no idea.
I was hoping the lovely people here on the forums might know of some way, or have advice on how to do this if there are no rules.
By design there is no way for the character to influence which perks and quirks; you either roll randomly or the GM picks ones that fit the story of how the item acquired the perk or quirk. This is because they aren't intentional efforts by the crafter but instead little unique flourishes that give that particular item a little bit of character and difference from others of its kind.