I'll redo the same process now, but instead of using the huge 37 mask, I'll use a 9 mask, this will be technique #2:
So once again we have the original picture:

The new 9 mask(tech#1) on left, 37 mask(tech#1) on right:

2x

5x

10x

The 9 mask almost makes the picture look nicer in that it reduces noise... However the 37 mask is about 25 times faster to compute.