Personal Training Advice Please?

You first have to ask yourself when it comes to feeling bulky "do I want to build less muscle to burn less calories at rest" What I mean by this is that by doing higher reps and lighter weight you would be taking away the benefits of increasing your muscle mass at a more substantial rate than using a heavier weight at lower reps does. It always comes back to the diet. If are eating too much and the wrong foods, you will become bulky. A lot of people don't know this or even see the pictures of female fitness competitors but they have an off season where they try to gain muscle mass which leads to a bit of fat gain so when they diet down they have more muscle "tone" I would keep doing what you're doing and just watch your caloric intake. The females I have trained over 10 years as a personal trainer that looked the best are always the ones that have used heavy weight so I suggest you keep your reps 8-10 on each set. Good luck.