If an app installs msvcrt, use it before Wine's builtin one?
That could theoreticly create legal problems, but it's OK for me.
I used the default values of documentation/samples/config. If those need changes, it's best to do so there.
I don't really care, but I personally prefer using builtin only (But that's a personal view)
Then those people use rpms or debs. And in that case, it's usually already configured out of the box if the packager knows what he's doing.
I (Following the example of codeweavers, at least until preview 4 that's the last I tried) use winesetuptk for packages. If you give a default config, you impose something that users may not want and may not know how to change. If you use winesetuptk, you give the user a choice of using a real or fake windows setup, and the user can also choose where to have it. The only difference is that codeweavers has a fancy pop up that asks you to run winesetuptk if it doesn't find a config file, and I'm not codeweavers, so I use the "By Alexandre" vanilla source (Otherwise it wouldn't be a official build anymore). Anyway, the config will go soon, so there isn't much point in discussing this.