Will dig it out.
In summary it goes something along these lines if I can remeber back..
Do you always use manual calcs or software such as CARD or Octopus WINPEP to pick the best mix of TOPL/Flex/Flap/Runway length/OAT/Pressure/Vmcg? V1 as a "go speed" or V1 as a "stop speed" etc... etc... etc...
Most of it targets the best flex for a set of atmospheric conditions and steadily adds flap to keep the best flex. If runway length is not limiting and you can go from an intersection it will quite often be the case that the V speeds will increase to keep max flex, but the higher speeds will give a better angle of climb out (increased V2) until V1 becomes a player as a V1 go speed or V1 stop spped. Because us pilots can't have a V1 range, the tables pick the best or the lowest safest of a range and calls it V1
If you use card and are using a long runway try forcng a flap 1 takeoff - think its code 30 and then run somefigs for any flap and quite often there is no difference in the flex but a big difference in the V1 and V2 speeds
