All I can say is I did not bench bleed and I have a dual reservoir and I have no air in my lines or my MC. There is no difference between a MC that is bolted to the frame and one tightened down to a vice if both are level. I agree that a firewall mounted MC should be bench bled as it probably isn't level.
Everyone doesn't say bench bleed. Several guys (mechanics) I know never bench bleed.


~Jim