longer crown needed

[little]

Hi, I have a Seiko 5Y30-5060 [ poor mans cartier tank louis ] and would like to fit a longer cabochan crown to resemble the cartier[ sad I know ] are all crown threads a standard size or am I restricted to fitting a Seiko crown and stem. I would also appreciate knowing whether there are specific suppliers of crowns/ stems or do I just look on the world largest auction site. Many thanks jack.

[MADDOG]

Have you tried Cousins.

[little]

Hi Maddog, Many thanks. To show my ignorance who or what is cousins please. thanks jack