HSV-1 is less susceptible to
Valtrex and related drugs, so the necessary dose is unknown
and might be higher than for HSV-2. Also, asymptomatic shedding is less common with oral HSV-1 than genital HSV-2. Finally, the main strategy for protecting your partner probably should be for him or her to be tested for HSV-1. There is a 50-50 chance of a positive result, in which case s/he is not susceptible and you need take no precautions at all.
To the specific questions:
1,3) Answered above.