I've seen a lot of references to folks seating their bullets to the lands... since I'm fairly new to reloading and all my ventures thus far have involved measuring factory ammo of the same bullet weight and seating to that depth.

The basic understanding I have thus far is you can use a specially made gauge OR notch a case neck and de-burr, place a bullet in the case and use a dowel or similar rod to push the bullet forward (gently) until it stops then removing the case; measuring the OACL and seating to that length.

First question is if this is the correct procedure; the notching case method as I don't feel like spending $30 or more on something I can make myself for about $1.
Second question is WHY should I be worried about this vice just sticking to the SAAMI/reloading manual's OACL... in fairly easy to understand terms.

Thanks in advance