Greek yogurt has the same consistency of butter without all the fat and calories. (bitesofflavor.com)
No I don't think that you can make it too thick, in fact I imagine it will only improve the final consistency of the butter: Good luck in finding refined coconut oil. (plantepusherne.dk)
I only had unrefined coconut oil, so used that knowing there would be a coconut flavour, but I really just wanted to see the consistency of the butter. (plantepusherne.dk)