Hi everyone!
Thanks so much for the response tomy question it has really cleared up some things
. When I asked if we can assume a higher weight for take-off I was refering to the same graph you use to attain your V1,Vr,V2 speeds and if your speed were to fall in the shaded area you would simply stay in the same column and just assume a heavier weight by going up the column until your speeds were no longer in the shaded area and then select those speeds provided you weren't limited in other areas such as field length.
Thanks again.