More loft makes it easier to use a fairway wood off the fairway so in that case a 5W and 7W would be best. If it's distance off the tee that you need then I'd go with a 3W and 5W combination.

Distance wise, relative to your driver the 3W will be anything between 20 and 50 yards shorter depending on how long and how well you hit the driver. 3-woods these days are like drivers of a few years back so they hit the ball a long way. You can knock another 20 yards off for a 5W and another 20 yards again for the 7 wood.