With a normal Red Devil Paint Shaker it would take about 2-3 minutes to thourougly disperse liquid pigment in a gallon of base house paint. I would think with plastisol pigments being much thicker it would take that shaker probably 10 times as long to disperse the pigment and then you are introducing alot of heat to the ink.
You are talking about the little pneumatic shakers by Red Devil.
Would never use that.
Shaking introduces a lot less heat to the ink then mixing or stirring.