The traps were worn high so that the belt line will be pretty much over your stomach instead of on the hips so that when the traps were set on your person they rode slightly below the belt line to keep from flapping about. If you've ever tried running with full kit on you'll know why everything was kept tight to the belt line.
On the haversack, cinch up the extra and sew it down as it was one size fits all and you had to adjust it yourself.
For the canteen, I think I ended up making the knot close to the canteen itself so that it wasn't that visible (one still had to stand for dress parade) and wasn't on the shoulder interfering with the musket strap or the knapsack straps.