feeding 2-3 prey items a week is pretty much power feeding the boa. technically you would have to force the food down the snakes throat to "power feed", but since the animal doesn't really know any better than to eat when there is food you are essentially power feeding or severely over feeding. the reason that you should feed only one per meal as I understand it is because even though boas have the ability to expand their stomachs width wise, they can not stretch it out length wise, so if you are stacking multiple prey items one after the other in the boas stomach it will not all be able to fit in to the stomach to be digested. all the portions that are outside of the stomach will rot quickly, which will poison and kill the snake if it does not regurgitate it out. have you ever left a dead rat in a very humid, hot environment for more than a day? I have and I can tell you that they get very nasty very quickly( the worst smell I have ever had the displeasure of smelling) so imagine your snakes boddy as the hot humid place and think about what that quickly rotting rodent could poison him with. and once you have a young boa regurgitate, if you are not very very very careful about how you handle the problem the boa can go down hill very quickly.
you have to remember that snakes are not like mammals, or even lizards, they do not have to eat on a regular basis to stay healthy. they are designed to go much much longer than 3 weeks with no food and still be perfectly fine. so it would not hurt your boa at all to go 3 weeks without food (I'm sure that little guy could go much longer than that with no problems). and if they do go long periods with out food you do no need to make up for the lost meals with extra food it won't do them any good.
the bottom line is that if you keep feeding the way that you are feeding you will either kill the boa before it reaches adult hood or severly shorten the snakes lifespan to only a handful of years instead of 20-30.
and as for the hand feeding, if he is not a good striker buy some tongs and feed him with tongs; or easier still just drop the (dead, please only feed him prekilled or f/t rodents ) mouse in the cage near him and let him crawl up and grab it. even if he doesn't see it at first he will go and get the food quickly. by feeding from your hand you are only asking for trouble for both you and the boa. snakes are not very smart, but they can make connections between events. so if you feed the boa from your hand he will eventually realize that whenever he see's your hand he should start striking- because surely food will be coming from it. that makes things very difficult for the keeper because every time you go to change water dishes or simply handle the boa he will be looking to grab the food from the hand that he knows always(in his simple mind) brings him food. snakes aren't really bright enough to understand the concept of not bitting the hand that feeds them, haha
good luck, and I hope that you take all the advice everyone gave you to heart.
Jon