From Costa Rica with a 13” dob (as Wouter mentioned, M83 is an easy one):
NGC 1566: Bright, large, elongated 3:2 ~N-S. With careful viewing the halo extends to ~3'x2'. A spiral arm is attached on the west side and curves towards the north beyond the main body of the galaxy. On the eastern side a low surface brightness arm is attached (on an E-W line with a mag 12 star close following the galaxy) and extends a little to the south on the eastern side of the main body. I was surprised to see the spiral arms so clearly!
NGC 1433: Fairly bright, large, oval 3:2 WNW-ESE, broad concentration with a large halo. The overall dimensions are ~3.5'x2.2'. I had a strong impression of extensions or the beginnings of two spiral arms (sketch made and verified); one arm begins at the west end and starts to curve towards the east on the south side while the other is symmetrically placed on the following end and hooks west on the north side. On images these arms connect to form a perfect barred ring.
M83: beautiful view with easy spiral structure in excellent seeing conditions. The main central portion of the galaxy appears to be in motion, due to the embedded spiral structure and darker ribbons add to this impression. The three principal arms extending from the galaxy were well seen although they are fairly tightly wound to the main body.
Steve