The handle length and shape is important too.
Flat is easier then round.
Balance also is a factor.
Too handle heavy or if the sheath carry's to high,it causes problems.
I can carry a 9inch bowie with the right handle and sheath IWB Appendix carry with the right cover vest or shirt but it's a stretch.
The bottom of the sheath/blade get in the way at times.
The right 6 inch is no problem.
Carrying IWB takes a good system.
Sheath,handle,knife and how it all hooks together in your wasteband.
I have a nice 6inch Persion double edged knife that's very flat and it's thin in the kydex sheath. Very easy to carry.
I have other knifes of a simmiler size that are very difficult to carry because of the problems I mentioned above.
I've carried a gun and knife IWB every day for over 20 years.
You learn a few tricks.
