Yes, I agree. The height adjustment on the stock rack should offer enough adjustability, and even more on the Wasp rack. I am 5'10", but more of my height is in my torso than normal cuz I have just under 30" inseam. On the chart, I was right on the borderline between medium and large, but since I will be commuting on the bike in my work uniform, I went with the large. Those two love bug seasons that we have here in Florida can be hard on white shirts.
When it is super hot and I'm not commuting, I may just switch back to my stock windsheild for day trips.