I have seen lots of good answers as to what to use. Most of them seem to be about Huggies. Here is my experience, though. I had a son who peed through his diapers constantly also. What I found out from some research is that Huggies may be one of the most absorbent diapers out there, his urine stream was to FAST for the the diaper. So, some would absorb, while some would not have time to absorb and therefore leak out. You will just have to try other diapers and see what works best for him. Our experience was that Pampers absorbed faster and didn't leak near as much while also having a fairly large threshold for amount.
The same thing with the "inserts" (pads and cloth diapers). Some cloth diaper materials have the same problem (we are cloth diapering our 4th child). So, just give different brands and styles a try and see what works best for your lo. If you do use a re-usable cloth of any kind......make sure you don't use fabric softeners or detergent with additives. That can actually slow down the absorbency of the cloth and create the same issue.
Good luck!