I rode with a pair of Tourmaster something or others for a few years. They were nice, but I had the same knee protection placement problem, along with the fact that they were about four inches too short.
I tried on many a pair of overpants and every one had that same problem. They were a perfect fit off the bike, but with my knees bent they would be too short and the armor would rise above my knee.
Last year I just so happend to be riding through Duluth MN (so sue me if it was a bit off the GPS's charted course) and stopped by Aerostich's little shop of wonders. There I tried on a pair of Darien pants. Same problem. Too short when I got on the bike, and the armor placed wrong.
But the sales lady quickly informed me that this was indeed no problem at all. Out came the tape measure, and after a few pulls of the tape while I was seated on my bike, she assured me they could have a pair of overpants that fit perfectly.
I continued home with my Tour somethings, and a few weeks later a package from Minnesota arrived.
I haven't been happier with a pice of riding gear. Perfect fit, perfect armor placement, and very comfortable to boot. Yeah they're pricey, but they were made to my exact specs. In the U S of A.
I highly recommend the Aerostich gear to anyone who asks.
But that's just my opinion and it's worth as much as you paid for it.
-darrell