For years, I only had one razor: a "Super Bismarck" 5/8.
Last week, I received a Friodur Inox 7/8 in the mail, and
it's an entirely different shaving experience. I've been
trying to figure out why.

Obviously, the 7/8 is heavier, and the blade is wider.
That goes without saying, but what puzzles me is this:

The 5/8 razor requires a "smaller" angle of attack for
the same effectiveness; ie, the spine needs to be closer
to the skin than does the 7/8, for the same "quality"
shave.

I don't understand that. The spine on the 7/8 is
obviously thicker, but...presumably...the bevel angle
should be about the same as the 5/8 with a thinner
spine.

What's going on here?

"Malo Aupito" (Tongan for "Many Thanks")