Just so that new mamas reading this in the future know the signs of baby getting enough milk as a newborn I'm linking a good kellymom site below. Often breastfeeding moms are given bad advice at hospitals, so hopefully this will help a new mom in the future.http://www.kellymom.com/bf/normal/newborn-nursing.html
Here is a summary:
Pees: babies should have at least 1 heavy wet diaper for each day of life. So in the 1st 24 hour of life, baby needs one good wet diaper, day 2 = 2 heavy wet diapes in 24 hours etc, up until day 6, when 6 heavy wet diapers are normal. Baby then should stay at (at least) 6 heavy wet diapers in 24 hours for several months. Heavy wet = the same as 3 tablespoons of water in a clean diaper.
Poops: Babies should have at least a poop for every day of life until day 4, when they should settle at at least 3-4 poops a day. A poop is as big or bigger than the size of a quarter (25 cent coin in North America). By day 5 the black/green tarry meconium poops should be gone and yellow poops take over.
Weight gain: Baby will typically lose 5-7% of birthweight after birth. Usually day 3 is the lowest weight. This is normal. Any weight loss over 7% should be watched carefully and breastfeeding needs to be carefully examined to make sure milk transfer is good. Some babies may safely lose more weight (if mom had a lot of IV fluids in labour, for example) but should be carefully watched for breastfeeding (latch/transfer) issues.
Most babies regain birthweight by 7-10 days. If baby is not up to birthwieght by 2 weeks a good breastfeeding check is a good idea.
As far as your last questions - first of all congratulations! Sounds like it is getting easier for both of you!
Hand expressing a few drops before latching is a great idea! So is feeding before he gets frantically hungry as well (which happens so fast at that age!!) If you are going to supplement, not using a bottle is the best way to prevent bottle preference. Babies tend to like the fast easy flow, so if you can give your milk by cup, spoon or tube at the breast you'll prevent that.
Keep going, Mama! You are doing great!