Need die comparative advice for 30-06

[zfk55]

I'm now working with a Don McCoy M1 Garand, single shot competition rifle. Obviously it will take a full 8 round charge, but it was designed and built as a single shot rifle. For most everything I use Redding Competition dies, but I do have a Forster press and have been reading about their proprietary Bench Rest Dies.
Before he passed away, Mr McCoy had mentioned that neck sizing was an intended part of the reloading process for this rifle.
Can anyone with practical experience with both please explain why I might want one over the other of these two neck sizing dies?

Thanks for any advice.

Latigo