Will a breast augmentation revision with 100cc increase in HP give me much more fullness?

The breast has a natural base diameter, and this relates to the distance from the nipple to the bottom fold. If the implant diameter is too large, then the fold has to be lowered, and if lowered too much then a double bubble can occur. High profile implants may be part of the solution, but it is not possible to offer advice specific to your question because everyone's anatomy is different. A general rule of thumb is that 100 cc's is the threshold for a noticeable difference.

I would not generally agree with the statement that anything over 350 will give you the risk of a double bubble.  Your particular breast may have certain limitations, but without measurements, a consultation, and an examination, it is impossible to give you specific advice regarding your goals.  Consult a board certified plastic surgeon who can help you with your goals. Good Luck.

Thank you for the question. Generally speaking, the best online advice I can give to ladies who are considering  revisionary breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you're looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "C or D cup”  or "much more fullness" or "significant" etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate. Again, best not to discuss your goals and/or judge the outcome of the procedure performed based on achieving a specific cup size.
 3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery. I generally select appropriate breast implant size/profile after the use of temporary intraoperative sizers and viewing the patient's chest in the upright and supine positions.
I hope this (and the attached link, dedicated to revisionary breast surgery concerns) helps.