Yes, 10% is not good. Still, for a 10 to 100 GB database, 10% is a LOT better than the default of 1MB and as I said "Later you can go about tweaking them individually." and further, "I am assuming you would want to grow each databases based on various factors, including your personal knowledge of how the databases is used -- not something I could include easily in this script."

The point of this script is to show how you could use sp_MSForEachDB (undocumented SP, I know) to do this. As always, you are free to adapt it as you see fit.