JR Z9100 HVT servo case screws

[TSK]

I recently purchased this servo sed off the forum. One of the screws for the face plate was misssing (pictured: top center)



I tried contacting horizon about a replacement, but have gotten no response. i know that they sell it with their replacement case set, but that over $70 + shipping.

Does anyone have/know the size of the screw i need to replace it?

Thanks