Should I massage to help my breast implants drop a little? 1 week post op, 300cc HP under muscle

You should follow your surgeon's advice, as massage is not always necessary. The purpose of breast massage after augmentation exercises is to keep the scar tissue that forms around your implants following surgery as soft and pliable as possible.You are still very early in your recovery and your breasts will settle in about three to four months. Please wait until then before assessing your results. 

The artificial volume immediately after breast augmentation is due to swelling. Massage particularly if it is vigorous can actually increased swelling. To my patients I give the advice that they should leave their breasts alone.

You can certainly massage your breast gently to move implants in and down as tolerated. It will help with softer capsule formation and possibly dropping/settling them down in dissected pocket.

as some don't believe in it since there is no evidence to prove it works.  In my practice, I'm a believer that it helps position the implants in where you consider it to be ideal.  But since your surgeon doesn't mention it, ask him about it and if the answer is 'not needed', follow advice and then when it comes time to critique results, if your implants remain high, express your concerns to him and hopefully there is a revision policy that you can utilize if needed.  Bottom line, your surgeon should want the best results possible for you so follow your surgeon's instructions.