"How long should one wait in-between fasts? I would like to do another one again, and would like to what is the healthiest waiting time."
How long was your fast?Was it water only fast?Age?In my opinion if it was short one,say from 3 to 10 days with proper break you should be able to reenergize your digestive system full mode and I think this should be the factor that determines time b/w fasts.
"Also, has anybody had any problems with lightheadedness, balance and eye floaters right after breaking a fast?"