>> 2. When I load a HTML string using TIpHtmlPanel.SetHtml the inter paragraph gap is too big.
Under Mac OS X, I find the inter paragraph gap to be non-existent, so you have the oppsite problem
I solved mine (for a help system) by changing the HTML to get the desired result (my SGML training cringes at doing this, but one does what one must).
So, what HTML elements are you using which creates these large gaps?