Sitecore: Powerful but mystifying

My Quickflix project (codenamed: phoenix) is going well and working with SiteCore has proven to be a challenge in both the best and worst senses of the word.

Articles on the net seem to be a bit thin on the ground when it comes to some of the more advanced areas of the application and it is proving to be a bit of a struggle. While the API documentation is great, finding out what certain parameters mean and also how / if I can do things is proving to be difficult, often ending up with just going back to trial and error.

If anyone out there has any knowledge about the following, or can point me to some help that would be great:

Passing fields as parameters to renderings: is it possible? can you do it from within the content editor? I would like to have a rendering that allows the user to specify some values from fields in the template (like the background image to use) but not actually specify the value, just the field to grab.

Can I write Sitecore or ASP control references in XSLT templates and still have sitecore render them? This would be handy in some of the controls I am trying to build, otherwise I will have to build ASP controls and write a heap of logic behind them, rather than just parsing the XML.

So far I am pretty happy with SiteCore and I am enjoying trying to meld it into something that will be easy for the content managers to use, whilst still allowing a heap of flexibility in page layout and functionality. Baby steps.