I tend to associate the "mali slap" to a more closed slap. I take Soungalo as an example for that. Ibrahima Sarr has a similar slap in terms of sound, though he must be the fola with the strangest hand position I've seen. I got the Tasumakan tansole lesson and noticed that Paddy has more of what I call a Mali slap.
Of course, I've seen on videos folas from Mali without this "mali slap". And also their style of solo phrasing more like what I associate to guinean style.
What makes me wonder is seeing more and more young guinean folas with this strange hand position, where the hands are more inwards than the arms. If you can't picture what I'm refering to, take as example Abou "Cobra" Camara, or Bamba Camara.
My guess is that this is related to the fact that nowadays, a dejambe fola has access to a highly streched skin from early age, wich didn't happen to the older masters.
As for the hand position to make a slap work right in a not so high tuned djembe, I take as example Gbanworo Keita, Laurent Camara, Noumoudy (from the footage recently added in ytube) and Famoudou. If you look at the older footage from Les Ballets africains you see that. Djembes are not as highly pitched, and the folas hands are spreaded a bit wider than what you see nowadays, and maybe a little more into the skin.
I believe that the shape of the shells have evolved too.
And then you have another kind of slap that I call "the adama dramé slap", wich I've never seen on anyone, with parallel hands, way into the skin.
I find this matter of great interest as I have it always in my mind when I'm practising and searching my slap(s).
What I'm beginning to believe is that there are intentional slaps and random slaps. You think of a kind of sound you want, and you go get it. Some times higher, sometimes lower pitched, sometimes open slaps, other times closed. Sometimes you missed what you were aiming for, and sometimes you get a random slap because your mind was more focused on some other aspect.
this talk makes me wanna play...