A woman's G-spot is located approx 3 inches inside her vagina, on the front wall (think toward her belly button). Angling the base towards her ass will push the head towards her G-spot in a more direct method. That being said, every woman's anatomy is different, it might be worth exploring her vagina with your fingers to get an idea of where her special spot is, it will feel different than the muscle wall, a bit soft and spongy.

I too prefer my clit stimulated with a constant buzz rather than patterns. I would suggest maybe using 2 toys simultaneously. One for clitoral stimulation and 1 for her G-spot. A wand style vibe is an intense constant buzz that will drive her insane. Magic Force is one of my favs and a regular go to in my collection. For Gspot vibes, the head on Greedy Girl is well proportioned in my opinion, but again, every girl is different. Currently, that product is out of stock. Flexi Power might suit your purpose as an alternative. It's bendable and doesn't have the clitoral arm to get in the way, making it ideal to use with a seperate clitoral stimulator.

As for the rate of her orgasm, many women find orgasming from their clit is easier and often more quickly achieved. G-spot and blended (combination of G-spot and clitoral) orgams can require a bit more patience and practice in the right amount of speed, pressure, and arousal. Unless she is transgender, a woman will not have a p-spot orgasm, but for those that are, there is not a specified amount of appropriate time either. To help her achieve any type of orgasm, many women find buildup and anticipation coupled with stimulation to be the ticket. Good luck.