Mark, I practice "Minimum control airspeed" at a safe altitude. When you can do this with no loss of altitude then you are ready to land as slow as practical. I use my indicated airspeed at that angle for practice, not calculated,true or GPS speeds only indicated airspeed. As you know your actual airspeed will not be accurate at that angle of attack on the pitot tube.
How long is your runway? I also practice flying in ground effect the length of runway and land each time as part of my skills at slow flight. Regards, Ryan N2XV San Diego,Ca. EAA Ch.14