Line control poles are extremely difficult to adjust under load. It is much easier to extend them on deck, lift the front end, clip it to the jib sheet up by the forestay.
Then push the pole forward, clip it on the mast, and shee tin to bring the sail around.
Racing rules limit pole length to genoa LP, not foot dimension. If you are not racing of course you can set the adjustable pole to longer than your genoa LP.