Quint can be used anyways, and there are very few cases where procastrination can be better for stalling...
Since you'll be killing lots of creatures, any growth will be enough to bypass it (unless momentumed, and IDK, but I think there isn't any growth-quint-momentum AI3), since any other creature brought to the field will be killed ASAP.
And the problem behind Procastrination is that the first blow of the summoned creature won't be blocked, so a 10 atk dragon will attack you when you are filled with 2/15 (aprox) scarabs and kill you no matter why...