[Avodah] Movement in a minyan

[Ben Waxman]

We all know RMF's piskei halacha about davening in a minyan with a 
different nusach. I was wondering how that worked with movement. 
Meaning, you move in way which is different from the minyan.

My most common experience is when I go to a Sefardi shul and they sit 
for many of the kaddishim. I asked a relative (a rav) of Rav Moshe's and 
he told me that in his opinion, Rav Moshe's psak doesn't apply because 
you can always say that you are in a part of the tefilla that requires 
standing. I never found that such a satisfying answer, a kind of a minor 
lie. Plus there are times when it is obvious that you are standing for a 
kaddish for which they are sitting.  Normally I stand because there are 
usually a few Sefardim who stand for every kaddish (I've been told that 
Moroccans stand for kaddish).

However on Friday (1st day Cholo Moed here) I went to a Sefardi shul and 
when we got to shaking the arba minim the differences were black and 
white. First the way they shake is completely different from my minhag. 
Secondly, they shake the minim fewer times than I do (only the first 
Hodu each time Hodu is said).

So I want to be l'tchatchila, should I have shook the minim the  way 
they do?

Ben