Share 'Hero Theme needs advice on Orchestration'

Hero theme pdf.     This is the theme i made today. There is no articulation or dynamics i just wanted to focus on the theme. I have used a string quartet to get down the basic ideas and am now ready to orchestrate the piece. I'd like to have the horns playing the melody and the violins etc. accompanying. Do I need a specific key for the horns, trumpets and flutes etc. for example "horn in F". wh…