I dont see how .25 and .5 kg plates will help?
I'd hold off on doing the prowler until you can squat 405. Let this be your goal.
Since when was clarity important?
Well you said in your original post you were taking larger jumps because of the difference in lbs/kgs plates so I suggested that you should get fractional plates because you can fine tune how much you have on the bar.
I would say clarity was quite important with what you do. I bet your book wouldn't have sold quit as many copy's if the content was vague and unclear.