Hello Divco one,
Renners have a complete kit for the 4 screw Tilly, some what pricy
$68, not sure what you need, the jets are the same as the 3 screw Tilly, I do have a few parts from one that I scraped, let me know what you need if this helps.
In addition some parts from a Zenith will also fit, such as the GAV needle, the tube and the choke driver.
Regards Brian.