Spec is actually a way of faking reflection highlights, be aware of that, but yeah in both.

Theres no difference as long as you use the right type of ramo for the input, a U ramp for the U input and a V ramp for the V input, otherwise you get it the worng way round and it wont do what you want it to no matter what the values.

yeah just tweek it till you get it right, making sure that you values are correct to start off with, if its on the spec you can have a preview in hte material node and then renderto tweek it to how you want it.