I don't know if you'll find much because most etplayers are not modders and don't know much about this stuff. Many of the infos you find around about these subjects (antilag, hitboxes, hit detection in general) are partially or sometimes totally wrong.
Just keep in mind that when somebody hits you you are pushed back in the server, before you can see it yourself. When you shoot, the server will take that position into account (the position you have in the server), when it has to determine if you hit or not. And if there is a prediction error that is *not* the position where you believe you are. Now if you say your ping is 48, the difference shouldn't be very high. The angle or direction of your aim is not affected by screenshakes so you will still aim in the same direction, but if you are pushed back the position from where you are shooting might change slightly.
There is a command to show prediction errors, it's cg_showmiss. If you set it to 1, it will write many error messages in your game console. Among these you should check for 'prediction miss'. That number tells how many game units apart you were, from where the server thought you were (sorry I couldn't explain better :p) ). Headbox is 12 units wide, Bodybox is 36. So you can have an idea if that distance could make you miss a headshot or if it's so tiny that you would still hit the head. Of course if your enemy is on higher ground, moving back would result in aiming higher. But don't worry, your ping is 48, you are lucky
Most of those models you find in those websites are old (etmain-style hitboxes) so the bodybox is reliable (for stand and crouch), but the headbox is not like that anymore in all mods (etpro was first, then all copied their new headbox, I think Zinx gave the source code for etpro b_realhead) now in all mods the headbox is exactly on the head. There are commands to show the hitboxes when you play, but you must have rcon or host a server with that config, and mostly those hitboxes are a bit delayed so they give you only an idea. The most important thing you need to know (imho) is the height of crouching bodybox, the headbox is always on the head.