Removing long path awareness from read-only app manifest?

I can usually muscle through a lot of these types of things. this one has me stumped though.
I'm trying to run calibre-portable however the developer has hard-coded a path limit to save himself from potential support inquiries it appears. He has been steadfast in complete refusal and dismissal to allow the user to continue after a warning or some such, let alone disable it entirely.

It worked up until the newest iteration of calibre 4x to 5x at which point it was changed.
the best ive come up with was some mention of writing ones own manifest to circumvent the brick wall/error about character limits/path limits.
I'm no programmer, you wont catch me writing anything except for the most rudimentary of batch files or robocopy scripts.

Accessing the existing manifest within the executable was easy enough which appears to contain the line which i'm assuming that if changed to will circumvent the restriction.
I could be entirely off base of course. Someone here would know better than I.

That being said, the two scenarios ive managed to run up against at current are either A) being able to extract the manifest and edit it, with no way to re-package it or B) attempting to edit it in-situ but being rebuked due to being flagged read-only.

Anything within reason I can do? I'm attempting to run/place calibre portable in my dropbox folder and its simply not having it.

Figured out how to edit it, well replace it more or less using Resource Hacker. Unfortunately it still presents the path limit error. Obnoxious.