I use Permatex black for all, including threaded plugs, but I caveat that I only use threaded plugs for the oil galleys unless I absolutely have to use a push in plug.
I do not get too concerned with sealing internal NPT fittings though, just basic fitting and a little juice. In fact, they get very little silicone on the threads, mostly to lube the tapered thread, but I don't like loose RTV (although it'd likely no nothing at that amount).
I drive in the cup plugs with a bearing driver, I have an adapter that drives the outside until it bottoms, then I switch to a deeper ID collar (or a socket that fits snug in a pinch), and the rear cam plug with a piece of 2x4 and then a big brass mushroomed drift.