Right, OK - pretty manual then. I was envisaging some sort of n-way diffing tool which simulates several staging areas and changes could be moved around line by line, maybe a button to run a build + tests for each in parallel. Gets difficult as soon as code in one of the middle commits needs a bit of extra tweaking to work though, I suppose.

I'll have to try it sometime, I have a feeling it wouldn't normally turn out too differently to what I end up with anyway. I do think all commits should build and run properly - otherwise git bisect and similar processes stop being useful.