Hi

I agree with Fynsdad that the milliput is a good material to use. I do mine with Squadron Green Putty but in exactly the same way with a screw driver - see pic of my current project. One of my pals has used the no more nails technique as well but you need to be careful as there are two types of the stuff so make sure you get a solvent free type otherwise it can badly attack plastic leaving you with a melted hull.

As for the Tamiya stuff, personally I did not like it as it did not look very convincing once painted. It was too smooth and the patter did not look right.

cheers
Gorehound