if u cant 1 shot the target with elemental katar, switch to status dagger? i thought it should be status katar 
Status katar can be used also but I wouldn't recommend it... Why did i say so?!
-Yes, you can inflict status ailment with Throw Knife when your wearing your status Katar BUT your not wearing your Cranial... get the picture?
-Why use [4] slots if your can use [4]+[4]=[8] slots?
For example, if your Throwing Knife on a target wearing your Dagger [3SK:Phreeoni] + Cranial and you notice that you are missing because your target has a very high flee... Why not wear a Dagger [4SK] + Dagger [4Phreeoni]? <--- exageration?

I don't think you'll miss on a 99 agi base stat target.
-Status Dagger because your inflicting the damage of your Katar + inflicting ailment your dagger.
For example, SB'ing a target using +10 Infil then switching to Dagger [4SK]... Your Inflicting the damage of your Infil then frosting it, there is a very high chances that the target will not survive your 2nd SB. Not like SB'ing with your +10 S.Jur [4SK], you inflicted the status ailment but there is a 50-50 chance that your target will survive your 2nd SB.