This is a great sight and most of the people on here ate really helpful.
As far as ur carbs leaking out the over flow could be the float but I put my money on the needle and seat. If the needles are old and they sit for a long they get a ring around the rubber where the needle comes in contact with the seat. You can pull the bowls of the carb that is leaking and look to see if y can see the ring. I just had the same problem changed the needles and seat and fixed the prob. Hope this helps.