I'd advise against doing Vyvanse & Coke in the same day. I mean, chances are it wouldn't kill you or anything, but combining two different stimulants together is rarely a good idea at all.
I know that whenever I combine Adderall & Coke, even if it's only just in a slightly overlapping sort of way, I always feel like my heart's about to beat out of my chest (something that I never feel from doing any amount of just coke or just amphetamines), & lots of the time I get really anxious & agitated to the point where I then just end up taking Benzos or Painkillers to make the effects of the combination go away.