What follows is a brief guide to the realstic rules, helpfully written by Kuno.
So you want to ref a realistic match, even though you probably shouldn't. I'm here to assist. While you won't become as awesome as me, hopefully it'll help.
Pokemon are tough. They are made to fight each other. And they do! I think the first line of this paragraph needs to be repeated a lot. Like a mantra. While there is a big difference between slapstick and realistic, they are mostly the same. One big difference is that Pokemon can have a stay in the Pokemon Center should their injury be large enough to warrant it. But I think we are getting a bit ahead of ourselves here. Let's start with the way the battle is reffed.
Reffing a Realistic match isn't too different than a slapstick. While injury can occur, it doesn't mean that it will. In realistic, it is possible to aim for sensitive areas to further hinder the opponent. This is where skills that increase accuracy have their shine in the ASB. Because in realistic attacks that require precision (in regards to aiming for sensitive areas) become more likely to miss the harder the target is. So what does this mean? Horn Drilling through the brain is going to have the defending Pokemon probably 100% likely to dodge if they are both fresh out. Pokemon that aren't lucky enough to be fresh out, and have suffered some abuse might find themselves getting hurt a lot. If a Pokemon is in a situation that will get them hurt very badly or killed, that Pokemon will do anything to get out of the situation, even if they were not ordered to do so. Pokemon have a little more brains here, since they can die. A Pokemon may try to do a Struggle or similar attack (See: Rage, attacks of their element, etc) to get away from the opponent or break free, without being ordered, to save their skin. However this will come at an exceptional energy loss. A Pokemon is more than happy to trade some energy to save themselves from dying or getting limbs removed or whatever.
However, what the above does not mean is Pokemon do not get magic auto dodge. They won't see an Ice Beam and go "Oh hey this'll hurt a lot, Kuno wrote about it in his thing so they get to dodge". You have to be smart as a ref and use discretion. What the above means is like.. a Pokemon being wrapped and is struggling to get free, for example. Situations where they know they are going to die or be in terrible pain, rather than just be KOed.
But stuff like what I mentioned above should be rare. Pokemon shouldn't be chopping off body parts left and right. While cuts and gashes will be common, those don't really require a Pokemon Center stay. Pokemon are made to beat each other up. That being said, injury should be rare. Being hit with a strong super effective attack will not cause an injury, unless it is an extreme situation. Such as a Pokemon weak to fire getting a full body burn from a Fire Blast. Something like that might require a stay, but Pokemon are made to take damage, and even super effective hits won't cause PC stays. Additionally, while some Pokemon are soft and squishy, breaking bones is not very easy. Pokemon weak to fighting won't start popping off limbs just because they got hit with fighting moves. Even being hit with strong moves, such as a Hyper Beam or an Explosion will not really cause much injury, unless the Pokemon is almost KOed.
Ok so you reffed a match. Even in realistic, Pokemon Center stays aren't common. Or at least they shouldn't be. Pokemon are high health/energy are not likely to be injured (bones breaking, etc), barring extreme situations. They are just fresh out! In addition, the use of the move Recover can (or at least should..) be able to cure most minor PC stay injuries. This means cuts will heal and bones will fix, etc. The description says bones can be "set wrong" but I think Archy wrote that and he's a cuss. Cuss him. If a Pokemon Recovers on the field with major injures it should fix most problems, unless they are pretty bad. This is probably the only move that works a bit differently in Realistic. So how long should a Pokemon be in the PC? Bones and stuff should be a round, stuff worse than that is really up to the ref.