I just had my 9,1 acid out in good size waves today ...the rails really bit into the wave ..and i enjoy the paddle power that comes with a 9,1 board ,
my 8,7 flow however takes a bit more paddling .but is looser on the wave ,which i would say the smik 8,6 would be too ..yes i noticed the rails are quite chunky and it does have 135 litres over the 9,1 at 125 and 8,7 flow at 120 .
you would surf them different ,I had a rip on the 8,3 smik ,it was loose ,but felt a lot smaller than the acid .duh,me .
I'm getting my 8,7 placid next week it has 31.5 wide and 125 litre simular to the 8,6 ,I will do a comparison soon ..for ya .but it still won't be a smik,
but at your weight boots you could ride the 8,3 ,I was 98 kgs ..at the time ..and kept tripping over it

personally i don't like boards under 8,5 ,cause i'm a lump .
I love my acid .
