Should I top before fim?

Only if you like stressing the hell out of your plants. Would be better to do one or the other rather than using a high stress technique on them twice. Topping slows them down longer than if you FIM. If she's fast growing beast topping would be better to slow her down so the rest of her catches up. You will have a good chance of creating a nice even canopy this way. FIM for slower-medium speed plants to temporarily slow down the main stem growth but you will still have to do some wrestling with her along the way. It's a matter of preference. Good luck.