I wouldn't suggest putting two males together as it does tend to set up competition, however it could result in the male you want to breed being dominated or stressed by the other one you introduced as competition. This could have a negative result on your breeding plans. Better to stick with the scents such as sheds and sperm plugs, over the actual snakes. Your advice about rain is good. BP's tend to respond favorably to low pressure systems(stormy weather) for breeding.