Phil, I tend to agree with you in all points. Especially the last one on 'educated guesses'. That's all we have, for the most part.
But even if there's little evidence, it's still evidence. And so I just wanted to mention some conventional perceptions of this – conventional as far as academic research is concerned. There's always debate, of course. And, myself, I applaud bold contributions anytime.
If anyone's interested, there is an article on this particular topic/discussion by Ross Cowan in Ancient Warfare V.3. Good overview, good read.