Indentation in a patch

Hi,
I'm having a fight with git and indentation for my first ever patch
attempt.  I'm just adding an if statement around an existing 70-line
code-block. It's a very simple few lines with --ignore-all-space. But
the patch file is noisy because of 140 lines of +/- indentation diffs.

I then realised the standard was tabs, and after fixing my spaces,
things got even worse. The 140 lines now interleave in many unreadable
chunks. I've tried different diff-algorithms, but they make no
difference. I'm tempted to submit my patch without indenting the
if-block, and an explanation. Any better suggestions?

While I'm asking, I added a regression test and ran make check-world
with the TAP tests. Anything else I should do before sending it to
hackers?

Thanks, Bernice