I've fostered lots of newborn kittens. And have way too many failed to be adopted cats. If you were to bring in a full grown male, its possible that Taffy may start marking the house to show the other cat that its his turf. Bringing in a adult male is going to be harder than a young one. If the new male is strong willed, Taffy could get stalked and emotionally stressed. Young neutered male or spayed female (kitten) will be easier to integrate and less chance for Taffy to start misbehaving.

Integrating two adult male can be done but its lot more work. Sometimes, you only get to uneasy truce between the two.

You will also need to get a second litter box. Taffy has his own. He think it belongs to him and not to any new cat. Second litter box should be made available when you bring home a new cat. Also have several water bowls elsewhere in the house so that Taffy isn't protecting his "watering hole". And you will need a second food bowl just for the new cat. All for the same reason. What belongs to Taffy is HIS! Eventually, they will share the litter box and the water bowl. food bowl should be kept separate.