company permits the use of semi-permanent or 'fixed' de-rates, such as TO1/2/3
We use both fixed derates and assumed/flex..... but we dont use alternate forward CG, so regardless of the CG position, the V-speeds stay the same. Therefore i would say that the thrust has a direct impact on the V-speeds, the CG doesnt.
A 'mean' V1 is usually settled on by the system, depending on whether it's octopus,CARD, navtech, EPOC etc etc
By "mean" do you mean "Balanced"? Actually i would have thought that whatever software you use would give the same answer based on the users selected parameters. As all of the GUI's have to go back to the STAS software, the answer should be the same.
Mutt