Everyone does it a little differently. I myself am not consistent with how I do it. Also, if you don't smell or taste any diacetyl in the unfinished beer, you might not even need to do a diacetyl rest; HOWEVER, it will never hurt to do one either. Your plan looks good, 10 days then ramp up, that should work fine. Does it matter? That's a question I cannot answer with absolute certainty.
If you do need a diacetyl rest, then the best time to do a diacetyl rest is when the specific gravity points are half of what you started with. So for example, when a 1.060 OG beer changes to 1.030, or from 1.086 to 1.043, etc.