I don't know about #1 - I just can't remember the instructions on the first charge.
For #2 it seems to work best for us to calibrate around 2-3 times a day. I'll do the 3rd calibration if it seems like it is off more than I'd expect. Generally two has been enough to keep it close.
After using the Navigator for so long - I am just mentally tuned to trying to calibrate at the most stable times - and more when the number is in a fairly decent range. I still tend to do that and I don't know if it matters or not with the Dex.
mom to William, age 13, dx'd 3/04 and started pumping 10/04 - Animas 1200. Animas Ping started 01/09; T-Slim started 2/15; cgms Navigator start 4/6/09; RIP Navigator 9-1-11, Dexcom 7+start 10/11, G4 start 11/12.
and mom to Rod (17) not D