I've had the opportunity to see and feel 4 sets of fake boobs, all on thin girls of various heights. All 4 were massage parlor girls, and were done with the purpose of getting more customers & bigger tips:
1. Girl was about 5-5. Changed from an A to a medium B. Fascinating to look at because they stood out so proudly, but had the bolted-on half grapefruit look and felt hard.
2. Girl was about 5-1. Changed from an A to a D! Gave her a spectacular shape, but they were overdone, with way too much fullness on top, which made her nipples point down. They didn't feel even close to natural.
3. Girl was about 5-2. Changed from a small B to a medium C. First surgery left them uneven, with one pointing up more than the other one, and there was some scarring. Second surgery helped, but didn't completely solve the problem. 3rd surgery fixed everything, and they were awesome! About a year after the 3rd surgery, they softened up a bit and felt natural. She had originally been tempted to go for a drastic size increase, but she was ultimately very happy that she didn't. They looked, moved, & felt like nice firm real breasts. She was attractive before the surgery, but the change made her a real head-turner. She looked awesome in a T-Shirt, in a bikini, or naked. She went through a lot of hassle, but she said it had been worth the trouble. I agreed, because I visited her often and gave her lots of my hard-earned money. (I guess it helped that she also gave some of the best hand jobs on Earth.)
4. Girl was about 5-9. She went from a teeny-tiny, almost non-existent A to a small C. Because she was very thin, any larger would have looked wrong, but the small C was perfect. Seeing that tall blonde in a T-shirt or tank top, with her small but well-shaped butt, small tight waist, and perfectly sized & shaped boobs would give any guy a hard on. They looked & felt firm enough that you'd know they weren't natural, but they were still simply awesome. She was extremely happy with the results, and never had any problems. I was happy too, because I got to play with them while she was expertly bringing me to orgasm.
I think each of these girls got the results she wanted- more customers & bigger tips. However, I don't think I'd encourage any woman to undergo invasive & potentially dangerous breast enhancement surgery in order to please me. If she thinks it will make her more attractive and will make her feel better about herself, then I'd tell her to go for it, but research carefully, find a good reputable surgeon, and don't make the change too drastic. Try to leave at least a little doubt in observers' minds about whether those beautiful things are real or not.