The fabric store was out of the pretty robin's egg blue cotton that I used last time, so I went with more of a Kelly green. I also picked up a nice purple and a light blue with brown polka-dots, both of which I also intend to use for short-sleeve button-up shirts. I decided to cut the green first because 1) it was the cheapest fabric I bought ($4.99 a yd 40% off) so if I screwed it up again I wasn't out much money and 2) it was my least favorite of the three fabrics so I wouldn't be that upset if it didn't work out.
I am really happy to report that I didn't screw it up this time. Here is a picture of the flat fell seam on the sleeve cap. As you can see I did still get a little bit of puckering, but it is world's away better than my last attempt. I think it even looks better than the shirts that I made with plain seams.
And here is a picture of the shirt turned inside out. I used the clean finish for the princess seams this time and I have to say they are not bad. They don't lie perfectly flat, but then what would? They do look better than the mock french seams and they were easier to execute. Unexpected bonus: they were also easier to deal with when hemming and attaching the sleeves because they are less bulky. Not that I was surprised by that, I just hadn't thought about that aspect.
All in all, I am totally pleased with this shirt. It fits well and I managed to have all clean seams with minimal headache. I'm calling it a winner. I am going to make it again, although I think that next time I will add a folded down collar.