If your are on Pregnyl alone, I personally believe it is best to inject every day or every two days a small amount. Take a look at the Pharmacokinetic profile of HCG at the following link.
http://home.intekom.com/pharm/donmed/pregnyl.html
Maximal plasma hCG levels will be reached in males approximately 6 and 16 hours after a single intramuscular or subcutaneous injection of hCG, respectively and in females after approximately 20 hours. HCG is approximately 80 per cent metabolized, predominantly in the kidneys. Intramuscular and subcutaneous administration of hCG were found to be bioequivalent regarding the extent of absorption and the apparent elimination half-lives of approximately 33 hours. On basis of the recommended dose regimens and elimination half-life, cumulation is not expected to occur.
If your are doing weekly T injections, and you only add HCG to balance the dip at the end of your week, weekly injections do the job. (As per SWALE's protocol).