Actually, you want half the leg discrepancy for your blocks. I have a 1/2" discrepancy and use 1/4" shims between my shoe soles and the cleats and a 1/2" heel lift for when I am not on the bike.
I have one pair of shoes that a cobbler put a 1/2" lift on. If you have a pair of preferred cycling shoes that a cobble can modify, you could have him put in a lift that is 3/4" under the heel but 3/8" under the ball of your foot.
About using half the leg discrepancy for cycling. When I was going through PT and had just learned of my discrepancy, I did the mental gymnastics and came up withthe half. TRied it and liked it. (1/4" aluminum plale bent to match the curve of the sole.) Showed it to my PT next visit, She said that was exactly what she would have ordered. Been using it now on all my cycling shoes for the two years. Love it. FOr the first time ever, I get to sit on-center on a bike. When I look down, I see right down teh center of the frame. Mind blowing! (This after 52 years of riding crooked.)
Ben