Just be absolutely open with her about what you want. Openness breeds openness, the more open you are with her the easier it will be for her to be open with you.
Next weekend I should have some even better marks to show you, playing with a new girl who is a red head and marks easily and she says 'I want lots of marks, that will last days'.
She said her shoulders were sore the next day, I have had her doing yoga which helps with that, but otherwise it is usually not really painful. If your flexable, and have enough muscle endurance, no lasting pain is going to happen.
I prefer bound. I do not feel binding a sub forces submission, a restrictive tie is a greater act of submission to me than having her try and stand still. There is a greater level of trust involved when she submits to being restrained and losing freedom.