I know it's a smaller and different boat than the 23, but on my 192, I use 3/16" double braid polyester for the topping lift. It's tied to the backstay clevis pin up at the masthead crane, and led down to a 2:1 purchase on the end of the boom. That purchase is led forward about 3/4 along the boom to a clam cleat. This arrangement allows for less weight aloft, and ease of adjustment down below (except when the sail is flaked on the boom.

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I have it set so that I can store the boom level, or I can hoist the end of the boom high enough to provide standing room at the tiller for motoring or lounging around the cockpit. Yet I can still reasonably adjust the boom height to balance it against the vang and provide vang sheeting and set proper main twist.
I don't know that a 23 boom and mainsail would be that much heavier than 3/16" double braid could handle, but 1/4" would definitely get the job done as well.