The link you provided includes the following information that backs up what the others have said here, 6-7 weeks is too young to start vaccines.
When should puppies be vaccinated?
The length and timing of the window of susceptibility is different in every litter, and even between individuals in a litter. A study of a cross section of different puppies showed that the age at which they were able to respond to a vaccine and develop protection (become immunized) covered a wide period of time.
At six weeks of age, 25% of the puppies could be immunized. At 9 weeks of age, 40% of the puppies were able to respond to the vaccine. The number increased to 60% by 16 weeks of age, and by 18 weeks, 95% of the puppies were protected by the vaccine.
This falls in line with Dr Dodd's recommended protocol:
9 - 10 weeks -Distemper + Parvovirus, MLV (e.g. Intervet
Progard Puppy DPV)
14 weeks- Same as above
16 -18 weeks (optional)- Same as above
20 weeks or older, if allowable by law- Rabies
1 year- Distemper and Parvovirus, MLV
1 year- Rabies, killed 3-year product (give 3-4 weeks
apart from distemper/parvovirus booster)
W Jean Dodds Vaccine Protocol VACCINATION PROTOCOLS
Remember, too, that it takes about 2 weeks for antibodies to develop. So, sending a pup home at 8 weeks with vaccines started at 6 weeks would leave only 1 in 4 with any type of resistance to diseases.
Those aren't odds I would want to take.