I nap too, but splitting sleep up into two halves doesn't seem to reduce the daily quota. Currently I sleep from 10pm - 6am, take a 10m nap at 9.30am and 12.00 midday, then a 20 min sleep at 3pm. I work out twice a day, going unusually hard and I eat very heavily with the goal of putting on weight. I drink a small amount of coffee and take ginko and ginseng.
On this schedule, I only just recover between workouts, i.e. it feels like I am progressing at maxiumum capacity.