Angle of bat for backspin serve

but ma long's bat not totally flat its look like 30-40 degrees. you can see that this link https://youtu.be/iw2pwoh6zv0?t=1m16s

All different.  You can do any angle depending on what you want to do.

That's the problem . When learning to practice it becomes confusing . Can u send a video or upload in slow motion and just focussing on the serve and the bat. I am sure it could be useful to all

Also when I try to make it flattish my posture etc is not same as yours. The bat to keep it flat does not allow your stance or posture

Rakeshs is right.
I am fully capable of imagining various bat angles and swings during a serve,however,some close-ups to a serving bat would be very good when making a serve tutorial.
As far as the backspin serve,the fullest backspin is with horizontal bat.
However,this makes it harder to keep it low in my opinion. Thus I always try to keep it balanced and vary it.
Sometimes I do a slow horizontal bat swing,whereas other time I use about 30°,but fast swing,resulting in two nearly same services.

hi Alois

 

can we get a sliw motion video just focissing on the abgle of the bat and the serve

Yeee.... Alois,Please :))
This would be so good one :OO

Will put it on the list of videos... Thanks.