I credited deja and his detective skills earlier, since he'd sherlocked the difference in height. To summarize:
For the 7733/7734/7736,
Part 8000 is for a 30-minute counter and 8.2mm high.
Part 8000/3 is for the 45-minute counter, and is 8.9mm high.
There is no other difference. The gear has the same number of teeth, and I think it's only the heart-piece that interacts with the minute-recording runner.
Like Z3k0, my 7032 was converted using two parts. The chronograph works, but I'm not totally confident in it. The reset to zero is a bit iffy, and it doesn't as feel as solid as it did when it had the 30-minute gears installed. Mind you, I did drop the watch back in October, so that's one confounding factor. I'm still waiting for my 8000/3 to arrive from the UK. I'll find out then if the longer runner solves my chrono problems.