I recently found myself in a compositional pickle writing an electroacoustic piece for a solo double bassist (which included the performer doubling on cymbal). I constantly found myself in a stand-still thinking I could not even begin composing out the double bass part until I figured out exactly what the electronics were doing (mind you, I thought I had to figure everything for both parts in my head before I could begin writing down the double bass part or creating the electroacoustic part). What I discovered in that process (by accident really), was that I could write out the double bass part (just get a section done! written down!) and then just make the electronic part fit that. Waiting for both parts to be created simultaneously in hopes that both parts would be more cohesive (married/one/intertwined) was a waste of time and completely unrealistic.