I'm going to suggest avoiding forward facing. It doesn't foster the ideal hip position and babies can become quite overwhelmed and don't have any way to snuggle in to you to calm down or just hide. I had my ds on my back at that age, he was about that size. You can find videos for back carries on YouTube just make sure you have a spotter or try it kneeling on your bed. I think with the new Beco ( not sure which model) they can forward face keeping a better hip postion but they are $$$$.
I would avoid a front pack at all costs with your son being that weight you'll get nothing but a sore back and shoulders