Tuplets (was: Re: Sibelius user looking for the easiest way to learn LilyPond)

[Noeck]

> \set tupletSpannerDuration = #(ly:make-moment 1 4)

How about a command like \partial?
\tupletDuration 4 % equivalent to the above command

( The rare case \tupletDuration 4*3 would be
  \set tupletSpannerDuration = #(ly:make-moment 3 4) )

> Is there a possibility to either
>   a) split after the number of notes in the denominator* or
>   b) according to the base moment of the metre or
>   c) a combination of both?

Is there any comment, whether that makes sense?
Tuplet brackets are one of the few places that need manual intervention
for a standard use case.

Cheers,
Joram