Beefmaster show heifer questions!!!

[Briii2003]

I went to the Pasadena blow and go show and the judges said my heifer is very balanced and looks like she would be good breeding material but they'd like to see tighter dewlap and they want to see her gain a bit more muscle in her shoulders. First question I have is about the neck sweat, i have some time before the major stock shows come up and I bought a neck sweat for her... about how long do you start to notice actual change in the neck? My second question is what feed could she be put on to get her shoulders to bulk up