Hi,
This will likely throw a wrench into these ideas here ... but mine is poetry, and not quite music, though I can do some really goof Fripp'isms with the instruments I have and create words off the visuals and feelings while doing it!
All in all, I NEVER, go into it, with any ideas ... because, I might have a different feeling while doing it, and that means that your attention is now divided. Generally I start writing the minute the movie starts, and this accounts for my being able to write at work, at home, and what not ... it's the same person!
That said, there are times when the "visual" is continuing on, and you have to stay on it as far as possible ... the kind of things, that has a way of making it sound like, these ideas can not be used in music ... because too much of it is "self-conscious", and thus, any experimental process that works on getting rid of that idealistic process, is not likely to get a good reception with folks that only know and understand popular music ... and its derivatives.
Honestly? ... there was a mystic, that suggested that the minute you "find it" ... trash it! And you will be rewarded ten fold! In general, this only makes sense if you accept the reality that ... you are here and now and at this moment ... and an idea or previous theme is not (necessarily) here and now. When it came up, was the time for you to be there, not later or after, so you could explore the "moment", which would have given you a better idea of how to go along with it ... but if all you can look for in these areas, is another note, another sound, another this or that ... I doubt that you will ever be happy with your own work, and always think that you can do better than the last time.
This is one of the reasons, why I enjoy Peter Hammill so much ... it's about "now" and "this moment" ... and then it's over and the next album is totally different!
To "find" more moments, that help you find new things and musics, you have to "undo" the boxes and any learning ... so you can feel it through and through ... the rest is easy ... you already have the mechanics for it, and if you record it, you can always come back to it and correct the smaller details ... but I seriously doubt that it will change things in a major way.
This has been my experience in writing, directing and with actors. Musicians, generally speaking, have been the tougher group to work with!