Well when I reloaded I did a huge personal study on this with my .270 win M70. I bought a RCBS case mic and found the exact distance to touch the lands and set my dies up to this. Then I set five back .005", another five back .010" etc etc until I reached the normal factory length. I don't remember what that is now offhand.

What my testing showed me was that there (for my rifle and loads) was no advantage to getting the bullet close to the lands. The normal length grouped just as well without possible feeding problems etc. I also had more pressure signs when close to the lands (flattening primers etc).