I'm 6' and a bit, wear a 34" inseam, and weigh 175 in full leathers + gear.
Compared to my '08 Road Glide (now gone), it's not as easy on the knees. But compared to my '05 SV650 it's more than halfway there. I don't think you'll feel cramped on the 851.
I agree about the standard vs. Strada...