Create a lenticular lens mask

I am trying to set up a mask for a lenticular image. The resolution of the Photoshop document is 1440 to match the output resolution of my printer.

I create a 4px  by 6" shape that I need duplicated every 28 pixels for the full 4".

In Illustrator, this is no problem, but forget it if you think you can paste from Illustrator to Photoshop.

How can I get Photoshop to repeat this 4px shape every 28 px? It has to be precise.

And before anyone gets on about lenticular lenses not being exactly 60 lenticules/inch, I am well aware of this. By taking the measured lenticules from the pitch test using the same printer, I find that the actual lenticule size is 60.189 so when I make the mask for 4px--that assumes 60 screen. Then I just print at 60/60.189 % and the lenticules come out correct.