I figured this out working on my perk mod, and I figured I'd save it here for posterity, because there isn't another tutorial out there on how to do it. Hopefully it'll help someone in the future. Most likely me, the next time I need to do this, and have forgotten how.

Perk position is controlled by their SPECIAL requirement in the perk record on the first rank of the perk (subsequent ranks don't matter), which you can edit either in CK, or in xedit. So, to move a perk from one column to another, just change the Special Requirements, eg from Str 3 to End 2. Because it's a poster, with a defined number of spaces, every time you move something you have to swap it with something else (otherwise you end up with whited out perk icons, which the game loads as a default when it can't find something to place in a spot). This is fairly simple to do if you're comfortable in xedit.

Now, the problem is that for a lot of perks, doing this off-centers the icon, this is because the perk icons aren't all the same size and shape, they're tweaked in LevelupMenu.swf to make them look good. This is how you fix that.
 
- Open up LevelupMenu.swf in JPEX Flash Decompiler. You can get it from it's releases on Github: https://github.com/jindrapetrik/jpexs-decompiler
- Scroll down to Define Sprite (1928), this is what controls centering of the perk icons in the poster in game, the entry only has one frame, so drop that down too and you should see a long list of all the perk animations.
- The list here is the perks, organized by column/row, so 0,0 is Strength Training, 1,0 is the perk at Strength 1, etc
- Hover over the perk icon you want to move, get the sprite id, find that id in the dropdown (form sprite 1928)
- Dropdown matrix in the right panel. To edit anything in this menu, you have to click edit (bottom bar), make your change, and then save by clicking the save button (where the edit buttom used to be on the bottom bar, not save the file in the top bar). If you click off your change without saving, it'll be reverted.
- characterId controls what icon is displayed in the editor- changing this won't move the perk in game, swapping it allows you to actually see what you're doing. So, for the two perks you want to swap, record their IDs, and swap them.
- Scale x/y controls the vertical and horizontal stretching. Some perks need to be increased or decreased in size to make them look right.
- Easiest way to make sure this is right, is just copy it from where the perk was before.
- translate x/y controls the centering of the perk, on the x and y axis
Decrease the Y to move it upwards, decrease the x to move it leftwards, and the reverse obviously.
Or just use Free Transform to drag and drop it to where it looks right.
The easiest way to make sure the scale is correct, it to note down the values from the two perks you want to swap, and just exchange them. Translation is relative to the entire poster, so swapping the values doesn't work as nicely- but it's possiblet o calculate the offset from the grid reference.
Save the file, and load up in game to see the view.


How to Get In Touch
Join me on Discord
Support me on Patreon