I would get in touch with a weight pulling club near you, otherwise you are setting yourself up for an injured dog that doesn't know how to pull correctly. No weight until he is full grown, you can get him used to pulling around empty jugs or something but until he is a year or so I wouldn't put weight on him. Also you may want to have his hips/legs xrayed to make sure he is sound as well, were his parents pull dogs or health tested at all? Lot of leg issues in poorly bred APBT
these days. Not a "blue nose" either as stated, looks black to me but sounds like he could be seal.