I Want to Switch from 525g HP to 700cc Mod Plus? (photo)

The example you present is one in which the width of the breast has not been filled out as it would in a naturally large breast. You have noted that you do not like the "torpedo look".  The volume of the proposed implant is determined according to a woman's breast base width, and her height and build.  Since you are taller, a larger moderate profile implant in the size you suggested, around 700 cc, makes sense, but the same appearance would be achieved in a woman around 5'4" with a breast base of 13 cc or so with a 375 cc implant.

    The main point is that a high profile implant does not look good when it is too narrow for that woman's chest. In choosing high profile vs. moderate profile, most women are happy when their goals for size are met by an implant that is at or just under their breast width. When they want more volume, then the narrower, larger volume high profile implant, within reason, allows them to achieve that. 

    When women ask for larger implants that exceed their breast width, they should be informed that if such implants were used, they would greatly increase the risk of nerve damage, numbness, stretching of skin, malposition and need for future surgery.

The answer to your question depends on several things.  You didn't mention whether you wanted larger implants, you can can a larger base diameter with lower projection in the same volume implant.  A 3cm increase in base diameter is quite significant.  An increase in base diameter may not necessarily give you better cleavage, they may just sit further off to the side.  Only a live consultation can help guide your choice.

I understand your dissatisfaction with the space between the implants.  Simply going with larger implants may not necessarily solve the problem unless the pockets are also adjusted at the same time.  In my opinion going larger is a mistake.