Wolfgang Schuster:

do you need all of your fonts at the same time in your document?

Most of the time, one serif and one sans. I'd be happy to get these installed. Of course, High quality fonts often come in large sets. The varying weights turn up most often in the variations between different kinds of heads, occasionally in other things. Variations in optical size occur more frequently, besides in heads, in things like quotations, footnotes, and captions. Smallcaps (and sometimes, all-caps environments) often turn up in headers. It's nice to be able to switch easily between roman/italic and other things within environments like that---it's very nice if things like shape, weight and so on can be switched independently. It's also very nice if optical design sizes switch automatically with the current size. Consider, for example, something like this: a book on film with a header: "Fellini's Roma and 8 1/2". I'm used to setting something like this in this way: Fellini's \it{Roma} and \it{\cvfrac{8}{1}{2}} (where \cvfrac{}{}{} is a macro that gives me a compound vulgar fraction). The header is itself in smallcaps, so what comes out is: Fellini's <small caps> Roma <italic small caps> and <small caps> 8 <italic proportional lining> (italic and lining (i.e., uppercase) because it's a title) 1/2 <italic numerator><italic><italic denominator> all with minimal effort on the part of the writer. It seems natural that way.

Do you plan to switch between oldstyle and lining figures each sentence?

I've certainly done that before, with lining for quantities and oldstyle for everything else (mostly chapter and page numbers). Of course, other sorts of numerals turn up a lot too---the numerator and denominator variants for fractions, the superiors for footnotemarks and ordinals, and occasionally inferiors as well.

Do you need condensed and regular width together in the running text or do you want one in the text and the other in the header?

The different widths of my sans is one thing I hadn't counted on using much (I spend more time in serif) but, since I have the fonts, I thought it would be nice to be able to use them. More than the specific uses I've mentioned above, I'm used to the freedom of being able to use what I have when the need arises.

ConTeXt is not a DTP program and has a completely different concept.

I'm aware of that. I've been using LaTeX for fifteen years now. I keep hearing about Context and the work with Luatex and I want to try it out to see whether I can get higher quality. Loading and switching fonts is just the first hurdle. If it's too difficult to do this in Context, that's okay. I realize that it's a work in progress and these things may be improved someday. I just want to get as much working as I can right now so I can try out more things. I have two fonts to install. I've been at it for two weeks. I realize it might take a few more weeks and a lot of work. I know it's not as easy as dropping them in a folder. That's okay. I'll keep at it.

Before we can give you better answers think about what do want to achieve and where do you need a certain font feature and style, when you have a clear picture about this ty to describe it and we try to help you.