A final thank you (not really belated, I found them after the previous post) to cocoate.com
A flaw in my HTML mark-up was causing some screen elements to misalign on a few devices. Nothing really serious, it was just that the third column on the people page dropped on some of the less popular browsers.
cocoate's explanation of the 960-grid mechanisms was wonderfully clear.
Thank you folks. Or should I say "Merci bien mes amis"?