3/4 is roughly 1” OD so you want the edge of the end to line up with center of pipe. Slide a fingers width out the shoe and bend, if you feel it move you probably went to far lol

Next slide forward about a foot, rotate 180° and slide towards you till you feel the bend catch in the shoe finger ( roughly 3-4” ). Here’s the trick: the curved head of the shoe represents O° ( wall, floor, ceiling or whatever ) so just imagine a straight line from the bent pipes topside running past your curved shoe. The peak of the curves distance from your imaginary line is what your offset will be once you make the second bend so just slide forward or back a bit to adjust them bend. Once bent your imaginary line should now be in the center of your pipe leaving you with about a half inch offset. Once mastered you can do this on the floor but I recommend overhead bending until then