non comforming suggestion
I agree with "mercop" on the blade length for self defense; who could argue with him anyway?
But I would add that with the 5 1/2 length limit, you have restricted yourself to a partial handle length; if you are going to have a blade any larger than
an Exacto hobby tool.
Measure your palm. Approximately four inches, right? That leaves a remainder of 1 1/2 for a blade. Should you increase the blade length, then, you will be having less handle to grab on to -in a defensive knife.
My suggestion would be a "Tops Knives, 'Baghdad Bullet" for between $78 to $99, or the four inch blade K-Bar. Both in 1095; good old steel. The Bullet has a full length tang -good, and a nice Kydex clip on sheath. Wipe them dry, that is, do not permit them to be long term damp or wet, wax the blade, and they will hold up to corrosion fine.