1
there is a small technical movement when you release ken.
that small twist with your thumb and finger for some degree turn
this will make the spin of the ken straight (silky smooth / stylisimo / proper )
2
-try to get your one-turn realy consitent (duhh) and try to experiment with a slow turn and a fast turn...
- when your pulling harder for the two-turn swing, try to have the first turn under the tama / your hand ... now if your make eye contact with the spinning ken ... its a one-turn spin to follow with your eye's on to the tama
(well this works for me )