[Daz]

The arching they describe here means having the wrists level or even uncocked in TGM terms. So this relates to #2 not #3. Zeroing out #3 is normally accomplished by gripping in the palm of the left hand which is advisable for putting.

Id also say that in the photos the putting greats all look to have a flat left wrist and a bent right wrist (wedges in tact throughout the stroke).

Ball position is at or just ahead of low point and they certainly are NOT "keeping the putter face square to the line". They are on plane and tracing a straight plane line which is why the putter faces have rolled open and travelled back, up and IN. Not straight back straight through like Dandy and Peltz would have you do.

The hooding they talk about as well is I think them describing how they go from a bent left wrist at address to a flat left wrist for impact. Dandy recommends a left hand forearm controlled stroke rather than the right forearm control we would use with the principles of TGM.

Thats my take anyway.