Easy. I go for a ride before I tape the handlebar. (I just tape the cable down with electrical tape.) Bering the tools to adjust stem height, bar rotation and the brake lever clamp. Stop and adjust as needed. My hands will tell me what they like. After a couple of rides and the levers feel dialed in, I tape the bars from the bottom with cloth tape - so I can easliy unwrap ti the levers, move them and re-tape - as many times as I want. When that tape wears out, i put the good stuff on, knowing the levers are "right".
What other people think of my lever position is none of my (G** d***ed) bvusiness! I have to live with the consequences of hand issues if I get it wrong.
Ben