in my previous outfit on the 777 we had a ballpark v2 that we used in case we thought performance was compromised and then hit toga if necessary which seldom is on the triple...
And I used to do something very similar. I'd run an OPT calculation with no derate and take note of the V2. Should anything ever happen, I then had a safe V2 speed at hand to accelerate to if desired with certainty VMCA would never be an issue. I would however never advocate trying to accelerate to the higher speed if there was a significant difference between the two; in that case just have to live with it