If you have a halyard shackle with a ring or similar above it as in that picture your current hook should work fine as long as you tie the halyard to the shackle bit and not the top bit. as you normally only need about 10mm lift to disengage If your current hook is not quite disengaging then you can file a bit off your current hook. Some boats need to have the spanner pulled quite hard to engage or disengage the halyard can you post a photo of your current set up. Personally I think the link above shows an overly exact and complicated setup for a simple halyard lock