Bill,

I don't believe you can wall backwards. Maybe like piano or drawing, you'll need training to find your past profficiency if you'd stop for a long time.
Personnally, I can practice MAP program, and find convenient to do so, on Saturdays and Sundays. Nevertheless, I practice everyday in the week in travel time at around 1 hour X 2 per day.
Therefore, I can train at energy raising, mind taming, even sometimes trance.
This way you can learn everyday.
And As MAP book says , "Practice, practice, practice"...