Shanks come in many sizes, some are made for flat doors and are long, others are made very short for tower tubes. I have some 2 tap towers I drilled holes to make them 3 tap towers. Measure twice, cut once. For doing 3 taps you probably want to offset the height to make it easier to assemble. Get the original one out of the way, measure, drill, assemble and then replace the original. You can see in this pic the 3 tap towers, two faucets are removed. You could turn your tower and place them like mine or have the extra faucets lower instead, reversing the pattern.