When and how to begin reconditioning?

I keep thinking about the fact that I've damaged the reward centers of my brain by building certain associations through the use of pornography. I wonder at what stage in the no-PMO is it appropriate to re-introduce self-stimulation using imagination. Given that the difference between imagined scenarios and real scenarios is miniscule to the brain it would seem that stimulation + imagination would be an effective tool for reconditioning ourselves to normal stimulus. It would seem that if we've damaged ourselves by building bad associations simply abstaining from these associations will remove the negative stimulus but won't build a positive stimulus to create the appropriate conditioning.

On this theory, in the evening I achieved erection using imagination (which I am happy I can once again do after a month of no-PMO) and engaged in very limited self-stimulation, both in terms of duration and intensity of stimulation. The result was incredibly strong morning wood the next morning which is something I haven't had in years now.

Does anyone have any experience with a timeline for this or specifically the best way to do it?