Interesting technique.
Though you said you use it because you are not good at visualizing (an action I guess), but in my own experience, you don't need to be able to visualize correctly for the "the phase" to happen.
If you do it at the exact good moment and under the exact right brain wave/chemical condition, the visualization process becomes very realist by itself and one second later you are in the dream.
At least this is the way it worked for me each time I managed to enter the phase, but I must admit it was under the influence of galantamin.
What I mean is that even though I wasn't able to visualize correctly my 3 chosen mental action, it didn't matter since when the WILD/DEILD window is ready it becomes easy, natural and very realistic for few second and it is enough to let you enter in the dream.