Sorry for not reading all of the above properly, but maybe a noteworthy remark - terminology.
In the world of Airbus computerized calucaltions (FOVE, LPC NG, FlySmart, EFRAS, TOPAZ ... it is actually AFM Octopus implementaions) there is no OPTIMUM V1. If the results provide V1 speeds range (see FEHoppy above), then the choice is to display one of the following to the user:
- available V1 speeds range
- V1 min
- V1 max
- V1 mean value
The OPTIMUM term is typically used for (increased) V2 value, but not for V1. In line with 172_driver's
Every situation is what it is, no one size fits all...
on a given day it might be optimal for crew to choose one of the extremes. Thus, for the educated pilot's airline, displaying the full V1 range is the optimal choice.