I love the studio pro's new features. The palette knife "lock Rotation" control is pretty handy...but it's a bit of a pain to change it so it's just right.
A short cut key would be great in the future...one that would lock the angle where ever you have it when you press the hot key.
anyway, a simple solution i found to getting it at just the right direction quickly is to hold CONTROL(PC) and drag in the direction and length you would like it to go...just like making a strait brush stroke with the brush tool or line with the pencil,marker etc.
simple right? You may have already figured it out yourselves, but if you haven't I hope this was helpful to you
RAGE ON my friends!