Pictures would really help here... It's a bit hard to tell what you're doing wrong with the specular. spec power is from 0-100 so you'll need to add a multiply node with a large value (eg 50) to get a normal highlight. Oh and I'd suggest having a look at the existing materials that are in the example levels that come with…
From what i know you use a lerp for the spec power. The gloss map goes into the Alpha of the lerp then you make 2 constant nodes plugin the highest spec value in A and the lowest in B. I belive thats how it works.