I tend to agree with your trainer. You want the dog to see the weave poles as one obstacle, with a defined entrance, not as a series of different moves that require handler direction. She should be focused straight ahead, not checking in with you.
The nice thing with 2x2's is it really teaches the dog to find his own entrance. We never trialed, but Jack would nail the weaves from any angle in class. I think the key is to practice at home, about 3 to 5 minutes a day with a high-value toy and quit while she's still excited so she wants more. You really need to toss that toy to get her running out past the end of the poles; if they learn to slow down in the middle, they can sort of get confused and fall out of them.
Weave poles, done correctly, are a muscle memory thing. That takes lots of repetitions for very short sessions so she doesn't burn out.