Fred gave you the bottom line but let me give the summary by question number:
Q #1: Is there somewhere that shows how many are active in the forum? In a particular category?
When you first log into the forum, scroll down to the bottom and look at the forum stats and users online on the main forum page. It won't show you what they are doing but it'll show you the users who are currently online in the forum.
Q #2: QU108 - Under the "Job Properties," far right window, I've selected the Printer, Media size, and a custom Red River profile. Does it matter what is shown or selected in Media Type? If so, why?
Media type matters: you have to select the media type closest to the paper you are using. When you select media type, it sets the ink density, paper thickness, required margins, etc. for the paper you are using. Since your question 3 indicates you are using a profile, you need to be using the media type for that profile. You wouldn't want to be using glossy paper and have a matte media type selected, for example. And if you are using third party paper and a profile supplied by that third party for their paper, their profile
should come with instructions as to what media type to select and potentially even what quality settings apply for that profile. If your third party paper profile comes with no instructions, I suppose you could guess... but I'd be suspect of printer profiles that come with no instructions (settings): how good can their quality be if the person/company creating them doesn't know that every profile needs associated driver settings to be of any use.
I'll give you an example: let's say I buy XYZ brand glossy paper and download a profile from their website. The profile I downloaded says "Epson ET-8550 XYZ Silky Smooth Glossy" (which matches the name on the box of paper I bought) and I get NO instructions with the profile and there are none on their website. That profile is essentially useless because without the instructions on how to set settings in the driver, I don't know whether I should set media type to Epson Premium Glossy, Epson Ultra Glossy, or some other media type and I don't know what quality settings are valid for that profile. Third party paper companies do this all the time: dump profiles on their website with no instructions... when all they'd need to do is specify what settings
they used to
create that profile! Without that, as I said, the profile is useless. When this happens, you could ask them what settings are applicable for that profile but in my experience, you typically get a blank stare or an "it doesn't matter" response. I'm being a bit long-winded here because you mentioned using a profile and asking about media types and people who buy third party papers often have that question... for the reason I stated: they got a profile from the paper manufacturer but it came with no instructions as to the settings to use with that profile. Gotta just take those profiles with a grain of salt: try them but if they are not very good, you'll know why!
Q #3: QU108 - Under Edit/Preferences/Color Management, is it possible to add the names of third-party media so I can skip having to search the profile folder each time? If not, I'd suggest this as a software enhancement, unless it would cause some kind of other problem.
There should be no need to search. Ever. Unless the profile name doesn't match the printer (and media type) at all. And even if you do have to search, you only have to search once: you should be saving printer setups. For that, see Fred's post above. An example. You are using the ET-8550 and you are about to print on some (doesn't matter which) glossy paper. With the ET-8550 selected, select the media type for that paper and then drop down "Printer Profile" on the main window of Qimage on the Printers and Settings tab and select "Suggest profiles". That's it: no searching needed. The profile you need will be one of the top few selections and if you are using a manufacturer's paper, it'll be
the top profile in the list. But again, you only have to do this once. Once you find it, then save a printer setup under a name that you pick. Then in the future, load it by clicking the recall (folder) button per Fred's post and selecting that name: a couple clicks and you have everything restored down to the media size, profile, and all driver settings.
Mike