Safety gate advice

Upper West Side

Any safety gate and/or safety gate adapter recommendations for gates that have to be installed onto banisters at the bottom of a staircase?

We have a brand new staircase with beautiful banisters that I don't want to damage.  The baby gate that we received (Protect Auto Close Metal Gate by Munchkin) requires fixtures to be screwed into the banisters.  I've looked into adapters, but none that I've found have received very good reviews. 

Does anyone have experience with a sturdy adapter or a gate that works well at the bottom of the staircase?

 Thanks!