Tonearm - 5:57 pm on Mar 1, 2012 (gmt 0)

Yes if your are on a secure page then side resources should be loaded with the secure protocol.

Should relative links do the trick?

You can use client side triggering so js can do an ajax request to track something which can happen after the whole page is loaded. Or you can use the server script when the request is made and then customize the piwik to process it that way directly from your php.

I've read that the Piwik client script provides more information than the server-side APIs.