This is my first visit to this site. I owned and operated a Custom Interiors business in Southern Cal for over 30 years - retired not but thinking about doing some home stuff. 

In response to your question. We called what you're asking about "decorative nails, and "decorative nail strips". We never used nail strips in my business. They look too cheap. Decorative nails come in several finishes but most used are bronze and hammered brass, which look dented. Shanks are 1/2" to 3/4" long. 

The easiest and basic way to install individual nail heads is simply start hammering them in with a tack hammer. Get the first one in and set the shank of the next centered in the seam. While hammering the nail you can align it by hitting it off center or pushing it off center and setting it. I know of no other way to get a straight line. You have a seam to follow, so just follow it and tap the nails that are out of alignment gently. It's really a simple task. Just takes a little time.