I would avoid the Testors primer. I swore off the stuff 25 years ago when I discovered Tamiya. It doesn't lay down as smooth and doesn't sand as nicely as Tamiya. It may also be enamel, which means you can't put lacquer over top of it. Tamiya and Mr Color are lacquer, and you can paint any type of paint over it. I highly recommend Tamiya or Mr Color (Gunze Sangyo) primers as a far superior product to Testors.
Also, I noticed earlier that it was suggested you ditch the Tamiya masking tape in favour of cheaper regular household masking tape or painters tape. In my personal opinion, regular hardware-store masking tape is a bit bulky and difficult for paint work, and doesn't burnish into panel lines and deep contours as nicely as a hobby specific masking tape. It has its uses, but I find the expense of Hobby masking tapes to be well worth it for paint work. I keep Tamiya 6 mm and 18 mm tape on the bench and use it constantly for many purposes, less than 20% of which have anything to do with painting. Just don't leave it stuck to a painted model surface for more than a day, as it may mark the surface.