Destructive cropping

I have some 11x34" PDFs that I want to crop and save as two 11x17" PDFs. I've been searching online for info on destructive cropping. I've found some recommendations to use Examine Document and remove what it finds and also to use Remove page objects that are completely outside page and trim area using Preflight.

That doesn't remove it all though....it still leaves a good chunk of stuff behind. These are drawings exported as PDFs from Inventor. It removes all of the drawings and dimensions on the area outside the crop box but leaves the page box behind(probably because the page box extends into the area that I want to keep). I want the text and layers etc. to remain active, so I'm not converting to TIFF, cropping that and then converting back(I could OCR but I've found that something else I have to do with these PDFs runs into issues if I take a TIFF to PDF+OCR instead of getting a PDF from the source). I also have another issue that develops because the crop isn't destructive(auto-stamping after page insertion to a set rect value). I could work around it in the code(add a multiple of the length of a 11x17 in rect coords) but I'd prefer to fix the source of the problem.

The original PDF size for the DWG is 189 KB. After the semi-destructive cropping, it goes down to 156 KB. Part of why I'm doing all of what I'm doing is to save server space, so I'd prefer not to go from 96 KB(which is what TIFFs of the drawings take up and is what is being done currently) to 312 KB. I'd still be saving space with the PDF versions in the long run(due to other programs used down the line), it's just that I'd like to squeeze what efficiency I can out of this

I have a work-around for the time being. I could re-crop the PDF before I want to insert the second page and insert the same PDF. I'd still like to get some real cropping going on though, because I want this whole process to be fairly simple for the others that would have to do this.

Is there some secret additional method of removing content that I'm missing?