CANON XT 350D FLASH TECCNIQUE

i purchase an xt 350d and 420 ex speedlite and i have few questions to ask about the way of usisng the flash
1- fill flash in daylight
i did read in many threads that if i want to use the flash as a fill light in sunny daylight that i can use auto av or tv because it will use the flash as fill light because that the ambient light over 10EV then flash start to underexpose .. my question that if this is right so i do not have to make fec manualy to attain the fill flash?.and is it better in this case to use the ambient evaluative metering or partial ambient metering if i am shooting portrait?
2- indoor flash
i have 2 lens . the 18-55EF that come with the kit and i dont think that it use distance metering with the flash. the other lens is 28-105 EF II usm that have distance metering with the flash.. my question is when using the flash indoor as a main only light is it better to use the flash evaluative metering or the flash avearage metering??...i have noticed that using the evaluative metering give -2/3 underexposure ..so what you think is the best way to use here... and if it is the evaluative flash metering is this mean that i do not need to use fec bec it will do it automatically?
i appreciate any help ..thanks

1. I use FEC-1 or so.
2. I use evaluative, I haven't even tried averaging, and I don't have any need to right now.

Traditional fill flash in daylight as written about by the late Galen Rowell is usually about -1 and 2/3 FEC. It is designed just to fill in some shadows.

Be carefulk of nevec, seems to a problem with canon, where the camera relies more on the flash when using fill flash and purposely decreaes the background to better see the subject. If your subject is backlit and dark, then the camera works quite well, but when the scene is balanced, you will have a problem in AV mode, or TV mode I believe.
I will not take credit for this info, but to see more on the subject, look for a fill flash thread by me called ``fill flash help``