But can a blade have a somewhat soft feeling with koto
So by its name i guess it has a soft feeling.
I think you are starting to drive yourself a little crazy and now you are beginning to ask some of the wrong questions.
NextLevel really gave all the info you need to know.
You can have a blade where the top ply is hard, like Koto, and what is under it is soft, like most of those ALC blades (Viscaria, TB ALC etc) and it has a soft feeling but a hard top ply so a crisp feeling too.
But none of this stuff actually matters. Don't try and turn this into an attempt at logic. Try a bunch of blades out. Let how the blades feel in your hand help you decide what is right for you and what helps you get more spin.
If your coach does want you to get a blade that gives you more flex and more dwell for spin, good choices really might be things like:
Korbel
Primorac Off-
Innerforce ZLF
Innerforce ALC
Innerforce ZLC
But go ahead, read NextLevel's post again, maybe 2 or 3 times.
The truth is that you should ask your coach what blade he recommends. I would say simply use a conventional offensive Euro blade like a Boll ALC or Viscaria, but if those are still too stiff, then it means that your coach is asking you to really slow it down and go to something like an Innerforce ALCS or a Primorac or and Innerforce ZLC.
You come from a club with lots of good players and lots of people whose equipment you can test. I think you really should borrow blades from people around you rather than come to a forum like this.
So at the really reasonable all wood end - Primorac OFF-.
At a slightly higher wood end - A Korbel.
At a slower composite end - Innerforce ALCS or Innerforce ZLC.
At a faster composite end - Boll ALC or Boll ZLC or the ZOO equivalents if you prefer those handles or a classic Viscaria.
But you just have to hit with someone else's blade to get a feel for the speed and the feeling. Even if you think you play with power, playing with a slower blade will add spin automatically. A faster rubber like MX-P will reduce your swing output and let you focus on adding spin to the ball. This is probably what your coach is looking for.
That post is all you need. And that post could have just ended the thread. Everything you want is in this post.