Amazfit Watch faces

Hi!
I'm new to this forum. I bought recently a Redmi Watch 2 Lite and started wondering if I can create a watch face from scratch and upload it to the watch because mi fitness only allows a limited selection of watch faces.

But first, I needed to decode existing watch faces to a readable file format.

I finished writing a fully working watch face decoder for this watch, and now I'm hesitant on which file format I should save it to?

Thanks