I've been offered a period correct 24 teeth flat-footed crown for a Cal 321 Speedy. I've checked the dimensions based on MOW and OF posts and they are very close but not exact. Closer than the Railmaster or SM crowns that are out there. The outer tube diameter seems big though. I'm getting the inner dimensions shortly. I need expert advice on this, please share your thoughts. I've attached the images below. Thanks in advance!