Hiya...in terms of leaky bottles....these do NOT leak at all. They're the only ones I've found don't leak one little bit. They're expensive but worth it. However, if your baby is the one ;eaking milk when feeding it'll probably be a matter of trying different brand teats until you find one he latches better on. Have you tried th Dr. Brown bottles?
Does he take a long time to feed and dribble lots of milk and has he been like this from birth? This can be a sign of a tongue tie rather than a problem with the bottles. At 19 weeks you could try a sippy or doidy cup instead of a bottle and see if he gets on better with that :)
It could be that he's not getting his mouth around the teat of the bottle properly. We found this with the Tommee Tippee ones. They'd been fine for my daughter but my son just couldn't get on with them at all. We switched to MAM bottles (to try and help with his reflux) and found he had no problems at all with dribbling.
I use the MAM anti colic bottles with Isla & they do not leak milk at all.