h
i have used the cnc4you break out board you are using on a few lathe projects & never had any problems ,they worked 1st time & every , some times doing 300 parts with threads in a day
i used the proximity switch that you can buy from cnc4you , you have to mount these within about 20 thou's of your disc on the back end of your spindle but you have to use a disc with an extension leg because a proximity switch will not work with a slot , you also need to get a decent length of signal to get a very speed range , on my machines the measuring leg is 1" + in width this gives a very stable speed from 50 to 2000 rpm which only alters by 1 rpm over such a wide range & can thread at 600rpm for a 5/8" x 26 tpi thread
hope this helps
robert