I shaved with three sizes: 4/8; 5/8; and 6/8.
I felt the 4/8 had great maneuvering ability but felt too "small" in my hand.
The 6/8 was much bigger and felt "solid" in my hand, but had less maneuvering ability around my nose, chin, etc. The 5/8 seemed to have the good qualities of both. I now shave only with my 5/8 tortoise Dovo.
It feels "solid" in my hand and scoots around great.
Ron.