I want to work on and test 3 different versions of k2's category.php. I'd like them all to be deployed at once, choosing between them by changing the URL. Is this possible?

Here's what I tried that doesn't work:
I put three new files (categoryT0.php, categoryT1.php and categoryT2.php) in my template's html/com_k2/default folder.
I tested with a variation of the K2 categories URL that I get when I create a menu item for categories.
/index.php?option=com_k2&view=itemlist&layout=categoryT0&task=category&id=303

Only to receive this errror:
Call to a member function get() on null in .../htdocs/templates/jsn_time2_pro/html/mod_breadcrumbs/default.php on line 17

Oh, duh, I forgot the itemid. I would like to delete the original post but I can't seem to find the button.

No reason to delete it, it might help other users :)