It's awful kind of you to be willing to test a 200+MB pdf file to check for errors, seriously, but then it wouldn't be using your time wisely as given the size of the document the only decent way of converting it, even if it wasn't for k2pdfopt crashing by the size, is to multi-instance, as I just did. Also the command line interface (following your syntax) seemed faster than what the gui achieved. Converted the document in 8 separate files in a whoosh, now to merge them and test on kindle
Thank you!
EDIT: on a side note, an automated script would be best in that it will be able to evenly distribute the pages number between instances, and automatically merge them with almost no intervention for the user, but that's only if you really have spare time for that; I understand those constraints, being a hobbist coder myself.
EDIT 2: I tried jpdftweak, and either it's not working for me, or it is so counterintuitive I am not doing the correct thing, but it's been working for a long while now and I have still no output (had to increase java maximum useable ram as well).
PDFSAM tho, is definitely straightforward and in a nice graphical interface told me the percentage of processing and had the merged file ready in a short while, I am reading on my kindle now.