[Avodah] R. Asher Weiss

[Eli Turkel]

If one of us and the gadol hador were on a desert island and there were
only one kzayit of matzah available for pesach and it was our property,
Hashem would get more nachat ruach if we gave it to the gadol hador to
be mkayem the mitzvah (and we should act as such - although iiuc we
would not be compelled to)>>

On the contrary I don't see the heter of giving up a mitzvah to
anyone. I don't where it matter who has greater kavanah as affecting
mitzvot.
In another context it is discussed in great detail. In the holocaust
literature there are teshuvot of people who wanted to give up their
lives to save a gadol.
As far as I know they all conclude that it is strictly prohibited.
Similarly in a hospital if an elderly man is attached to a machine he
cannot give up his place to save a younger healthier person (possibly
a son may be different). Though not the same I dont see how a person
can give up a mitzvah so some else (greater) can do it.

<<Shliach shel adam kamoto applies only to the technical kiyum
hamitzvah (not sure if this extends to schar) but not to segula of
mitzvah (e.g.mitzvah gorreret mitzvah)>>

I don't know about segulot. However there is a debate among poskim if
one can light chanukah candles only late at night is it preferable
that one light it late but by himself or preferably ask someone else
to do it for him but at the proper time. I believe part of the
argument is the importance
of doing itself is it just a hidur or more than that.

kol tuv

-- 
Eli Turkel