Posaune's draft is the classical Rundschau draft and it usually gives a very good result.
Note the relocation of the centre front sleeve seam to match the side seam of the jacket.
I think the draft you used does not correspond to the shape of the armhole.
Easiest way to get a matching sleeve around the front armhole is to copy the shape of the armhole from the front sleeve pitch to the side seam.
Make Äe and S of both, sleeve and jacket front match and copy the shape of the armhole.
Another way to do that is to put both sleeve parts together at the front seams first and then place Äe of the sleeve on Äe of the jacket and copy the shape.
Drafting and cutting a Rundschau sleeve that will be pretty close to what you'll need isn't that difficult.
First you have to measure your armhole height(without seam allowances):
Front and back divided by 2 gives the final result. Then measure the armhole width (Umf) from 27a over Äe, S, h.Äe to 19a and again divide it by 2.
You will also need the final armhole diameter which you'll get by measuring straight from Äe to h.Äe.
The formula for the sleeve cap height is:
Just replace the numbers in the image with your ones. So it's 1/2 of Ah minus (1/10 of Ad plus 1-2cm). In a case of a classical jacket you'll need a higher sleeve crown, so it's 1/10 Ad plus 1cm.
The ease in the sleeve should not be more than 10% in general, depending on the fabric. I would recommend to use about 5-6% ease, which is appropriate for all sorts of fabrics. If you want more roping just open the upper sleeve a bit. In order to do so draw a line from the crown height to the vent corner:
You can use the same technique to reduce the crown width.
To determine the distribution of the ease subtract the width of the armhole from that of the sleeve and follow the instructions in the diagram:
There is no ease in the area from Äe to S. In the jacket pattern mark Äe1, which is 1/2 from Äe to Sch, and Äe2, which is 1/2 from h.Äe to Sch.
Depending on your percentage of ease add it to the distance of Äe and h.Äe to Sch to get the corresponding marks in the sleeve crown (you'll get a new Sch in the sleeve crown).