Applying the idea of Forward Writing to Composing Music

I was recently inspired by a post I stumbled upon about the concept of forward writing. I've read several books on writing that preach the wonders of free-writing, but the post brought it back to my attention. Free writing is the idea that you let your writing pour out like a stream, keeping the pen or cursor constantly moving forward and not worrying about editing.The article reminded me of an app called iA Writer that features a "focus mode". Basically only the sentence you are currently writing appears in the center of the screen in full black text, everything else around it fades into soft gray. If you really had to, you could look back and read what you just wrote, but the fading is amazingly effective in getting you to only think about the current sentence. You are forced to pay attention to the present moment in your writing, not what you wrote before. Mindful writing.I've been using the app for about a week now for journal entries and blog posts and I must say I absolutely love it. I'm able to write so much faster when I just let it pour out. Of course another thing to keep in mind is that whatever you are writing is simply a first draft. You can go back and make it good later, for now you just have to get the words out. This takes off any pressure that what you're writing has to be any good and instead you can just let it flow. [Even this post is at least twice as long as anything I might normally write up here, but it didn't necessarily take twice as much work. The app just made it easier to write.]Write first, edit later has been a mantra of mine for a long time, but when it comes to writing music it's much easier said than done. I often advise students to work on their sketches first, to plan everything out, to avoid orchestrating before the actual composing part is done. But I can have a hard time following my own advice at times.When working in a program like Logic it's just so easy to go back and play what you've done so far. And when you know that you want to use the french horn on that sweet melody you just wrote, avoiding the temptation to drag your region onto the horn is nearly impossible. Of course you want it to sound good right away! I won't get into the reasons here for why this becomes a dangerous trap.The important point is that writing first and editing later produces better results, but what can we do to make that happen? iA writer is a fantastic tool for using this technique when writing words, but what about music? Composing at the piano helps considerably, because you can't get tempted by all the gizmos and toys enticing you in Logic. Want to hear that melody on the horns? Well you're just going to have to wait.I suppose a musical cousin to free writing is improvisation. Just set record and improvise your heart out, let the piece flow out of your fingers. This is useful to me when I'm just trying to come up with ideas, but I'm not sure if it's really the best way to compose a piece of music. Maybe I just need to try it more, but it seems like there would be a lot of fluff to cut out just to get to the good stuff. It seems like there has to be a middle ground between bar by bar (and previous bars) composing, and free improvisation, but what is it? Where is the equivalent "focus mode" that allows you to see what you've just written if you need a guide, but also prompts you to keep the line moving forward? Is there such a thing, or can there be?Unfortunately I'm not providing the answer in this post, at this point I'm merely posing the question and putting it out there. Perhaps someone reading this has encountered this problem and solved it themselves? Or at least it will get someone else thinking about it with me.How do you turn the "stream of consciousness" benefits of free improvisation into practical use in structured composing?