For my Diorama / modeltrain i made these Vinterled / Scooterpath / Wintertrail marker to 3d print them in HO scale (1:87).
The size of the cross is about 5x7mm The post has a length of 29mm and a diameter of diameter 1mm. My prints came out really good on my Elegoo Mars.
I hope you could use this for your dioramas. for a wood effect use a corse sandpaper to get some structure in the cross and use a dark wash after painting.