Rossi Rifleman

Hello all. I had a cheap scope on my RG3030 for a while, but it would not hold vertical adjustment. I've gone back to using the iron sights and think I want to try the Marble's Bullseye rear sight. I've read of some people needing a taller front sight, and some didn't. A fiber optic front sight might be a good companion to the bullseye rear but I'm not sure if I'll need a taller height. Has anyone here used this rear sight, and did you need a taller front sight? If so, what height worked for you? My original rear sight is 3 notches up from the lowest setting for a 100 yard zero. I'll need to order these as there is nowhere nearby to purchase them. It would be nice to order them together rather than paying shipping twice.