I would absolutely get a loos gauge. We use ours in a couple ways.

1. To set our tuning marks for diamond tension. We use marks on the mast and diamond wires to keep track of things on the water, but the gauge is important to make sure everything is calibrated.

2. To check tension on sidestays. We don't have sta-masters so this is a rather gross setting, but we like to make sure we are in the correct range.