How do I select a deinterlacing method?

There are three different places to choose a deinterlacing method:
gui tab, deinterlace plugin
video tab, deinterlace method (deprecated)
postprocess/chain reaction/tvtime

I have no idea whatsoever which one of these I'm supposed to use.  I've been
using the first one, but there's no list of methods to choose from.  Moreover,
the lists of methods on the video tab and in tvtime are different from each
other.

I'm hoping someone can tell me:
-- which place is the preferred place to choose a deinterlacing method?
-- Why in the world do we have three of them anyway?
-- If the preferred method is the one that doesn't have a list of methods,
how do I know what methods are available?
-- why do different places contain lists of methods that don't match each other?
-- if you choose a method in more than one of these places, how does it
decide which one takes priority?
-- what do the methods do?  The names of some are not obvious, and even the
ones whose names look obvious don't really make sense.  Bob is not what is
normally called bob, and I would think that "weave" and "none" would be
equivalent.
-- It looks to me like picking deinterlacing through tvtime doesn't respect
using "i" to enable and deinterlacing.  Is that correct?

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