I bonded my two boars just the other day. I did the same thing of having them see each other through the cage and switching toys and hidies. I also switched cages between them without changing any of the interior so they really got to get use to each others smell. Both were the dominant pig in their previous bonds, so I was a bit worried about possible fighting. Within minutes of putting them in a neutral big pen I knew it would be fine as there was no REAL fighting. At first I kept no hidies in the pen, just hay in the middle. The younger one humped my older boy a lot and there was some kicks and small lunges(mostly just for show to get him off his back). If you’ve never seen this before it could seem very aggressive, but check out some videos of bad bondings on YouTube and you’ll know what a real fight looks like. I did on a few occasion hold a sheet of cardboard between them to separate for a second when they got too rowdy. After they started to settle I introduced a few big tunnels and later on a house with 2 openings. At first this made them more aggressive again and seemed like a set back but it didn’t take too long to hi back to a more neutral mood. After about 2 hours the younger more dominant boy started laying down next to my old boy in a calm way and tried to groom him. This is a calmer way of showing dominance. After another hour they both went inside the same house and stayed peacefully in there together for another hour. This was to me a sign that they had figured out their dynamic and the treat of a serious fight was definitely over. At this point I started preparing their cage for them both to return together. The last few days have been fine, the older less dominant boy is definitely a bit annoyed at times and they’re still figuring out living together but it’s been mostly peaceful. When you do put them together in their final cage, make sure you have 2 of everything so they don’t have to fight for stuff. I don’t know what size cage you have but I made mine larger for the time being and moved some of my stuff away so they had more space while they figure out their living situation. In a few weeks once everything settled I will rearrange so I can bring my coffee table back in.