1) for wilderness survival 6.5" to 10"

2) for "urban jungle" survival 4.5" - 6"

for 6.5" - 10" I would likely want INFI but SR77 would not be bad as long as its coated (just my opinion).

for 4.5-6", Carrying a knife that long will likely not gain favor from the local police, regardless of what the blade length limit says. I would have said VG-10 but the length is just over what I would consider its limit. If its a Dozer or Busse Kin heat treat then D2 could certainly work. SR101 or INFI, of course, would also work.