Hi rhinogrey,
I would say that you have already "captured" everything you experienced during your breakthrough.
Our unconscious minds only need to "scan", or come into contact for long enough with an experience or information for it to be "absorbed" into memory, very much like water coming into contact with porous material, such as a sponge.
What it looks like from here - and I could be wrong about this so please research and make your own mind up - is something called "state dependent" memory. That is, the mental state or mood you were in when you were having the experience. (Not "The State", or "Big Brother" !)
There could be other ways of recalling your experience, such as self - hypnosis, or using other ways to re-create at least part of the state, such as duplicating the set or setting, (incense, lighting, background sounds etc) and see if that will help to re-trigger the experience.
Having said all that, it may very well be a good idea to leave the specifics of your "state dependent" memory where it is and ask for the wisdom, lessons, knowledge and inspirations that have been unlocked for you to come to the surface and express themselves through your writing.
If you have written a lot of music before, then that talent stays with you.
Having said that (again!) the answers to our questions lie within us. It looks to me that your experience does indeed represent a signal from within that you have had the right amount of time to rest, regroup and find a fresh new direction to express your writing.
Perhaps by writing, you will surprise yourself wonderfully at the new found creativity that is just "dancing" within to express itself. Do you think that "releasing" rather than "capturing" will be a great way to approach this?
All I can say really, is explore the possibilities and directions for yourself and make your own mind up to what suits you. I would hope for other viewpoints from other Nexus members, as you have really got me to think about a lot! Hope this is of some help and thanks for the post.