Am I a candidate for just tip refinement/alar base reduction or should I get a full rhinoplasty? (photos)

I think your nose would be served best by undergoing a rhinoplasty. The nasal tip as you mention can be addressed by a combination of tip refinement and an alarplasty. However doing this alone with attenuate the dorsal hump. I would suggest having this augmented at the same time to give you a better profile and a softer more balanced nose.

Hi, In your case a full rhinoplasty will be the option. With it, your hump can be shaved and a complete structural tip  narrowing and alar reduction can done. Great natural looking results can be achieved.

 An alar plasty can accomplish narrowing wide nostrils with an  excision of a small portion of skin at the base of the nostrils which accomplishes narrowing them.  This can be done under local anesthesia.  A full rhinoplasty would be required to shave down the dorsal hump, and refine the nasal tip, and narrow bridge line.  Thick skin in the tip of the nose will prevent refinement in that area so it is very important have realistic expectations what you are trying to  accomplish. Rib cartilage is only a last resort, and when grafting is necessary, nasal cartilage is the first choice.