1 month post-op. Why do my 470cc implants look so small? Should I have gone bigger? Will they drop and fluff? (photos)

Congratulations on having undergone the breast augmentation procedure.  I think that your plastic surgeon has advised you correctly.  Although online consultants will not be able to provide you with meaningful reassurance, it may be helpful for you to know that a significant percentage of patients at your stage of recovery will feel that they are too big or (more commonly) too small. I routinely ask my patients to wait at least 3-6 months before evaluating the end results of the breast augmentation surgery. This waiting time allows patients to (usually) physically and psychologically adapt to the new body image. 
From the physiological standpoint, it takes many months ( and even up to one year) to see the final results of surgery. factors such as swelling, tissue contraction, skin redraping, implant shifting etc. come into play. You may be pleasantly surprised wants to be "drop and fluff" phenomenon has occurred. You may also be happier once the swelling AROUND the breast implants dissipates and the implants' shape and projection become more visible. 
From the psychological standpoint, patients undergo an “adaptation period" during which time they get used to the changes that the surgical procedure I would send has brought about. Severe emotional swings can also occur after any type of surgical procedure.
Although I cannot comment specifically about your anatomy and its limitations, (generally speaking) every patient undergoing breast augmentation surgery should understand that their anatomic starting point will limit the outcome of breast augmentation surgery.    In other words, a patient's starting anatomy will limit how large of a breast implant can be utilized safely. The use of a larger breast implant (than what is safely "allowed" by the patient's anatomy) can be problematic;  potential problems include breast implant displacement/malpostion issues ( such as bottoming out, lateral displacement, symmastia...)  and/or significant breast implant rippling/palpability.
In your case, I would suggest continued patience and continued close follow-up with your plastic surgeon.
Best wishes for an outcome that you will be very pleased with long-term. 

Larger implants take longer to drop, particularly in smaller women.   Massage can help.  Wait 6 months for the implants to settle and tissues to relax before you determine whether they fit your anatomy.Kenneth Hughes, MD, ABPS Board Certified Plastic Surgeon Los Angeles, CA

You are still very early in the healing process and need time for your tissues to relax and let the implants settle. Right now, follow all your post operative instructions and please give yourself time to heal. Remember, this is the size that you and your surgeon selected. Have faith in your surgeon's decision.