Honestly, after using the 3M "Dry guide coat" #05861 I couldn't imagine going back to aerosol cans. It seems expensive at about $20.00, but it lasts a LONG time. I have been using a container for about at year now at work.
It is an extremely fine powder that gets into the finest of scratches. We are talking 400 or 600 grit. There is no overspray to worry about, no uneven spray pattern, it is simply the best way to guide coat in my opinion.
If you are going to go aerosol get a "real" guide coat product like SEM and others make.
Others will no doubt say it is a waste of money and "any old black paint" will work. I use to use "any old black paint" myself. I feel there is a big difference in how fine it sprays, now much more even it goes on and so forth. Besides, it is designed for the use, it just make sense.
But honestly, go with the dry guide, you will not be sorry.