Many years ago, when I first decided to try trekking poles. I analyzed how I would use them and decided that I would prefer cane grip poles. I've never regretted that decision. I've tried regular, straight grip poles, I have several pair, but I've never found them as functional as cane or T-grip poles.
Recently I upgraded to some newer Leki Wanderfreund poles.
These are fantastic poles.
For hundreds, probably thousands, of years, when the elderly or infirm needed a balance/support aid, they most likely reached for a cane, not a long, straight shaft. There is a reason for that. I don't understand why so few people have tried can grip trekking poles. Way, way, superior.
You can adjust them similarly to regular poles. With your hands on top of the grip, your elbow would be about 90 degrees.
More recently, I've been sizing them like you would a cane. Standing erect, with your arms hanging at your side, the pole should come up to the bone protuberance on your wrist. I kind of like this. You can put more downward weight on them. Don't believe me? Try lifting your body off the ground with your elbows at 90 degrees. Then try doing it when they are nearly straight. Uh, huh. See.