What about turning the rulers on in a new document , dropping the 4 cropped faces into it and using edit>transform make each separate face/layer fit properly into its quarter of the page using the rulers as a size guide ? When you use Transform hold the shift key down while you drag out the corner handle and the rectangle will keep its proportions and not get too wide or too tall. You can use the crop tool to further edit the sizes of your rectangles if you want them all exactly the same. There probably is another clever way but thats how I got it done for myself . I'd like to know if there is one thats less fiddly too. Hope this helps for now though

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python