Suwari waza probably wouldn't be the best against a BJJ person. Since they may very well attack you with their legs and pull you into the guard. For a skilled BJJ person this is a very powerful position. The minute you try to move they will be attacking your arms and neck in an attempt to upset your center with their hips and legs. (Make you worry about the attacks to the arms and neck, while their major purpose is to position you for a turnover, leg sweep, or a whole myriad of submissions.
Just my opinion. Take it for what its worth.