I got a chance to look at Jupiter under decent conditions early this morning. This is a sectional sketch where I sketched features as they crossed the Jovian central meridian--this is one way to keep up with the rapid rotation of Jupiter.
I've been wanting to do a sketch like this for sometime. It has the advantage of slowing things down, as you are just concentrating on what is visible on the central meridian (CM). With Jupiter so low, I had to leap ahead of the CM a little as the session progressed and the seeing deteriorated as Jupiter sank into the mush. It's still an interesting technique though, and I recommend that Jupiter observers try it.
I used HB, 2B, and 6B pencils for the sketch on recycled Strathmore paper. Blending was done with my finger. I used a circle template to render Io's shadow.
The very dark barge following the Great Red Spot (GRS) and the festoon extending all the way across the Equatorial Zone (EZ) were notable.
When I began the sketch, Io was just off the following limb. I could see it for a while inside the limb, but once it passed further in front of the disk, I could no longer make it out. Io's shadow was quite prominent. It moved across the disk faster than Jupiter rotated--its position is noted on the sketch at the end of the observation time--0600 UT.
Good luck with your own Jupiter observations.