help me choose:

looking for a razor to round out my existing 6 razors into a 7-day rotation. I am considering these:

5/8 round tip Ralf Aust

Boker Silver Steel 6/8

Thiers Issard 1937 Special Coiffeur 6/8

I'll be buying from SRD

My current rotation is:

Dovo Best 6/8
Dovo Pallisander 6/8
Burrell TOp Flight 5/8
Torrey 5/8
Grah Plumacher Silver Ring 6/8
Genco Army and Navy 5/8

I am hesitant to go for the 5/8 Aust as I think I really prefer a 6/8 blade.

Barry