Valin:

Inflight pics are OK but it's likely to be hard to determine the exact
elevator position unless the picture taker joins up just a few feet away
(not recommended, IMHO).

I also wanted to know my elevator cruise position, so I measured the
distance from the panel to the stick in trimmed flight and, once on the
ground, set the stick to that distance and then checked the elevator. (Of
course, since the trim system on my early 235 is spring loaded, aero forces
could tend to align the elevator somewhat but I reasoned that when very
close to neutral, those forces would be minimal).

I mention this method only because it's much more likely that someone can
get this data for you this way rather than going the in-flight picture
route.

Incidentally, I used the factory specified angle (LNC2 and very early) and
my elevator is very close to neutral in cruise.

Dan Schaefer