I don't have a Remington pump, but I did put HiViz sights on my Winchester 94 last year.  The difference was astounding!  I wanted better windage adjustments.  I found a 1/4 turn of the rear screw equaled 1" elevation adjustment at 100 yards.  With my handloads and the new sights, I can shoot 1 1/2" groups at 100 yards--with IRON SIGHTS!!!  
The HiViz were easy to put into the dovetails.  The rear portion slid right in; however, the front sight was a little tight, so I had to file some metal off the new front sight.  I think they made it that way to fit various makes.  I don't know if they make one specifically for Remington, but check it out.
Good Luck!