This is a response to the enquiries from Rebecca and Shams in the last post.
-How the supporting tape look?
-What is the advantage of "split sleeve"?
I still don't know how you call this type of sleeves in English, but I think I can explain what I like about them. I like split sleeves because (1) they are comfortable as much as raglan sleeves are yet they look less sporty. Also, (2) they are quite magnanimous to hobby sewists.
I prefer the appearance of set-in sleeves because they look less sporty than those raglan sleeves would usually do (from the front, of course). I have no problem with wearing raglan sleeves when I play sports because they are comfortable, but they tend to look too casual on me most of the time. Split sleeves are one of good solutions, imho.
Also, I think they are easy to fit when talking about sewing. Set-in sleeves need the right shoulder point to achieve a neat look, but split sleeves allow narrower shoulders as well as broader shoulders and stretchy fabrics as well as less stretchy fabrics to use the same pattern to fit wearers, because of their rounded shoulder seam. Easy fit. Not loose fit. I do like it.
I've taken some pictures to complement my writing. I hope you can imagine what I told about it.
P.S. I definitely need iron-on hemming tapes or a stick glue, for basting, to sew this curved shoulders neatly.