First the Radical French tip: When preparing this tip for application it does not matter if you use scissors or an abrasive, the object is to remove (not just a little but) just enough of the well so that when the tip is applied, it sits right on the smile line of the natural nail. In other words, the edge of the tip well is the smile line.
If using white powder for zone one, you will not even need to blend the tip. If using a wrap, you may want to blend for perfect clarity. Equally with gels unless using white gel, in which case it is the same as white powder.
The reason the Formation tip is so good for nail biters is that it has re-inforced sidewalls for extra strength, where the bitten nail is so weak, and the fuller well of the tip allows you to create the illusion of a longer nail bed by placing the smile line where you want it to be instead of where it actually is.