WGRS for H&R fit perfect on the barrel
but you may need a taller front sight
I put a WGRS on my 45/70 and needed to increase front sight height by a fair bit.
to find out what height you need.
measure the barrel where the rear sight sits divide that by two.
put the sight slider into its middle of travel, and measure from the middle of the aperture, to the deepest part of the base ( where the screw holes come through )
add that number to the above number.
now measure the muzzle diameter and divide by two.
subtract that number from the above number, and that will give you the aprox height the ramp/insert needs to be above the barrel.
another method, install the rear sight, and move slider to mid travel.
wrap and tape a stiff wire around the muzzle, leaving a tail straight up to act as a front sight.
shoot, cut, shoot, cut, shoot, cut etc until you have the elevation you need to be on target
( What ever zero you choose )
now measure the height of the wire above the barrel, get a ramp/insert to match that.