Re: possible OALD, trying to regulate...
Nursing only 5-10 minutes is very common with OALD. Babies get a lot of milk very quickly when the letdown is very fast. My son only nursed a few minutes on one breast for almost all of his feedings. As long as diaper output and weight gain are good, then there is no reason to worry about short feedings.
If there are only occasional green poops, then I wouldn't worry about foremilk/hindmilk issues. My son's poops were similar - numerous, usually normal, occasionally green and foamy. There is really just milk, although there is a gradual change in composition through the feed.
It's early, so your supply is still regulating. As long as you nurse on demand your body will sync up with your baby's needs. I would go ahead and let your baby nurse as quickly or as long as he wants and sleep as he chooses. I wouldn't be overly worried about finishing a side. What I did was offer one breast for an entire feeding (although every once in a while he would want the other, usually during a growth spurt). If he nursed only briefly and wanted to nurse again very soon after, then I offered the same breast. If he went more than 2 hours I usually offered the other breast, but only because I would be painfully engorged by that time. I think it is okay to offer the same breast for the next feeding on occasion, but I wouldn't necessarily do that all the time because that is getting into block feeding. If you are not seeing green foamy poops all (or at least most) of the time, block feeding might lower your supply more than you want.
If there is no pain with the spit up, then it is nothing to worry about. My son spewed spit up all the time. I covered myself in receiving blankets because burp cloths were not enough protection. Spit up is common with OALD and is nothing to worry about. There isn't much that can be done other thn frequent burping (which didn't help us much anyway).
Try bicycling your baby's legs very often and giving warm baths to help with gas.
K. Sophia - Mama to my little lactivore, the amazing Mr. X (11/10).