The only 2 things I think you might be missing are: Do you have a crotch strap or do you simply have a lap belt with shoulder harnesses? Second item is a helmet.
Having just survived a engine failure on take off at 200 feet off the end of Ryan field in MT just 6 weeks ago I can tell you that if my wife and I would have had crotch straps and helmets on we would have gotten away with just minor injuries. Instead we both have several badly compressed and fractured vertebrae, broken ribs, stitches in our heads. The lap belt/shoulder harness combo is great, but I realize now it is only half of the solution. Without a crotch strap your body can only go one direction during the deceleration process and that is down and out the bottom. This also vastly increases your chances of broken legs and or ankles. Your now bent nearly double, the lap belt has moved up on your torso, and the final portion of the impact breaks your ribs off your sternum. Broken ribs are no fun, and I am sure those of you who have experienced broken ribs can attest to the terror a simple sneeze or cough can bring. In the beginning the back pain was nothing compared to the pain and discomfort of the broken ribs. Unless you can sleep hanging from your heels like a bat you can forget getting much sleep, as there simply is no position in bed which will allow you to be comfortable enough to get any rest.
We are now both in upper body braces, ribs are pretty much healed, stitches are out, the back pain is low but constant. We are looking at 8 months to a year of recovery time with a slim chance of ever being 100% again. I too spent many hours and hundreds of dollars building my survival kit, vest ect., never giving much thought at all to the very real possibility that I in fact might not be able to get out of the aircraft on my own steam. Luckily for us there was no fire and thanks to all the great RAF folks who came to our rescue, we were quickly out of the aircraft and safely on our way to Kalispell Regional Hospital. Had there been a fire or we would have been alone at a remote strip the outcome would have been very different I am sure.
On a brighter note we are healing and with every day we are stronger, N397JL took good care of us but is a mess, we have a set of spare wings and have started the search for the other pieces to rebuild her, hopefully we will be back in the air by spring. This year was our first year at Johnson Creek, we met and made many new friends there, hopefully we will be back in 2012.
http://www.dailyinterlake.com/news/local_montana/article_17227ace-a12c-11e0-9054-001cc4c03286.html
Tear down by NTSB is yet to happen so we still don't know what caused the complete loss of power.
Best from Omak,
Doug and Kathleen Sapp