The hollow base doesn't make any difference to the powder charge, it's just to give the bullet a longer bearing surface. I have a box of those bullets but haven't tried them yet (I haven't loaded any .380 in a long time, and usually use 95 grain cast bullets)
Three grains of Green Dot sounds about right. And Unique is the powder for .380 (about 4 grains, but look it up) when you want your little mousegun to really bite your hand when you shoot it.
"The only way to stop a bad guy with a gun is with a good guy with a gun"