My suggestions (from experience)-
1. Import as 'Minimal' previews. It speeds up your import. Your Previews cache folder will be smaller. 1:1 previews can be created at any time.
If you have 1:1 previews, you can set preferences to delete 1:1 after a set time.
2. In Import [File Handling] panel- Remove a tick from "Add to Collection"
There is no need to create endless Collections of ALL your image files when you are "Adding" images to your catalog with Import. You will have your Hard-drive folder structure shown in the Folders Panel. There may be a need in future if you photograph a special event that you want to keep a 'Collection' reference to those specific images. (or a Book, or Slide-show)
The link had a lot of information, but I couldn't determine if it is worthwhile creating a preview of my JPG files which are typically 4000 x 2000 pixels and about 3 to 5 MB in size. I don't want to waste HD space by creating unnecessarily large previews if it isn't beneficial to me.
A further question: I will need to use 1:1 previews for my more recent images (past 2 years) shot in RAW. Can I have different preview options for part of my catalog or is it a one for all choice?
I would go with the "standard" previews. (See the Preferences dialog for optimizing them for your monitor.)
If you need a 1:1 preview later, LR can generate it as needed on the fly.