Amazfit Watch faces

Hi
I'm new to this site.
I am a proud new owner of a T Rex, a brilliant watch for the price.
I now want to create a new face like my Rolex style Milsub 1978.
What size do I create the images? I know the TREX screen is 360px, but do I create larger images.
Also once I create the images in photoshop is their anyone willing to create the final file for me to down load from the site.
I'm a Mac user and can't use the app suggested on this forum.

Look forward to a reply.

Rgds
Wayside

Following. Had same question about old Waltham pocket watch dials, especially the railroad grades with the second dial and power indicators from the 1930s or so.

I am JUST seeing this!! Beautiful! I love them. Will donate and download one.

Ps-- In your title bars you call them walthman-- that's wrong and I couldn't search them again when I stumbled over them and AW shuffled my faces. in other places you have it right-- WALTHAM. It's named after the City that they were originally made in. Other people might look too but they won't search "Walthman."

Thank you again! I'm excited!! Thank you!