>    The words 'hut' and 'heart', for example, are distinguised only by the
>    duration of the 'ah' sound.

In what dialect of English is the vowel of <hut> the same as the vowel
of <heart>?  Even in non-rhotic dialects where the latter is something
like [ha:t] I would expect the former to be either [hVt] or [hUt], not

>    the  'h' in 'huge' is objectively much closer to the 'ch' in German
>    'ich' than the 'h' in 'hunt'.

I'm not sure what this means.  Do you mean that the <h> in <huge>
is closer to the <ch> in <ich> than it is to the <h> in <hunt>,
or than the <h> in <hunt> is to the <ch>?

>    (vowels are typically shortened in English
>    when followed by an unvoiced consnant).

I thought it was that they were lengthened when
followed by a voiced consonant.  Guess it all depends on your point
of view. :)