I think Sim 100, which is 60% Nickel and 40% Titanium is the same as NiTinol. It is available from Alpha Knife Supply. Although the two piece knife may have a little more pizaaz and weigh a little less, I think the Sim 100 knife will be more practical and stronger. BTW, I think your last design will be a little more comfortable in the hand. I like it.
Tim
Tim