Positions P0-P4 all look viable, effectively the techniquie for install is
- palpate the area
- pinch and tent
- roll pinched skin between fingers (this ensures the veins aren’t “in the tent”)
- stabby stab stab
For an experienced installer, this shouldn’t be a problem.
The implant will naturally find a home and the vein or implant will give way to the other.
There are other places on the body you could install, but the back of the hand is good for blinky 
because the skin is thin and therefore easier to see the light.
Personally I wouldnt waste P0 for a blinky, but P1-P4 would be ideal, And if you are right handed I would put it in the Left so its easier to light up with a reader/phone