Add the vang
I haven't owned a 27, but I've seen several. As I recall, if you're on a down wind run and want to keep the sail off the rigging, you'll need to pull the boom down. You won't be able to do that from the travelor alone as it will begin to pull the boom back toward center. The vang is the appropriate alternative. A second alternative would be rig a preventor, but your vang could work for both.Jim