I've modified the way to mount the pack slightly. It just takes an added cam strap and some different positioning with the exisiting straps and you can carry a big boat on a short person. I'm only 5'8ish, and can easily hike with the large M3, which I think is over 8'.
Well worth the money for anyone that plans to do any hiking. It pays for itself after the first use. Also, it only takes about 10 minutes tops to rig up, is easy to use with gear stuffed in the boat, and cuts a lot of hiking in time almost in half. The only disadvantage is that if you are bush wacking or scouting it doesn't work so well.
I've done multiple hikes with it, the longest hiking out of the second gorge lime, about 2+ miles of uphill switchbacks. The Upper Taos Box hike out takes about 15 minutes with the pack.