Set play offenses allow you as a coach and your players to more easily control the temporal sequencing of cuts, screens, and when and where the ball will be placed. I think you are very much on the right track when you say you are running too many options. Your choice of set plays should reflect both who you want to get the ball at the critical time to score, and where, and how much of the clock you need to use while protecting a lead, or coming from behind. The set plays should give you potential quick hitters that you can use when you need to score quickly, however the primary options should be well into the shot clock as if you were protecting a lead. Remember that good scouting by your opponents will often take away your primary options.
Primary options work best when counters work equally well.
Remember too to practice all possible counter plays for each cut with enough repetitions so that you players will react automatically under pressure. This simply takes a lot of practice. I watched a top Italian Professional League team practice a few years back, where they spent almost 2 hours just running the same play over and over until the defense had tried to destroy each option and the offense was confident to score from both the primary and counter options. Finally, it is my opinion that winning basketball teams are confident to handle pressure. Emphasize the importance of this to your team and that it is an area you must improve to be the best team they can be.