Pruning Time Machine Backups

Here's an interesting twist; Apple seems to be protecting me from myself again:

I noticed that Time Machine (TM) is backing up the Thumb64Segment.data (etc) files in my iPhoto bundle/folder and since those files are large and easily replaced, I want to skip them; easily added to the exception list ("Do not back up", via the "Options" button in the Time Machine preference pane) for future backups - HOWEVER I can't figure out how to prune them from previous TM backups.

(Tip: If you don't already use Eriban's Grand Perspective, check it out - it's terrific for exploring just where your disk space is spent, and it properly counts the hard links that TM makes such heavy use of. BTW: I also recommended Robert Pointon's tms, a command line utility to get lots of great info on your TM backups, including what exactly was backed up each time.)

Now, back to the problem that software exposed:

Of course I can open the iPhoto bundle in a Finder window, but as soon as I "Enter Time Machine", the window changes and moves to its parent. If I first open a Finder window to a subfolder within the bundle, that does stay viewed in Time Machine, but as soon as I click on the Thumb64Segment.data file to "Delete all Backups..." of it, the window immediately moves up another level.

Apparently Apple wants to prevent me from messing with bundles. I do understand the reasoning, however I'd argue the protections in the Finder are enough; if I've explicitly chosen to navigate into a bundle (hard to do by mistake) then let me work there! :)

So, there appears to be no GUI way to prune TM backups of bundles in this way; does anyone know how to prune by command line, within Time Machine? Of course it's easy enough to simply find and delete files via command line, however I don't know if that's safe within a Time Machine backup - anyone?