I would not buy a S912 device at all
1gb will work, but you will struggle in some areas.
I recommend you get a S905(x) with at least 2 GB of RAM
Thanks mate, I though of the S912 because of the promising panfrost driver that is already in beta with GLES 2 working while the lime driver for S905(x) its still alpha
I saw that the panfrost driver will continue to be developed to adapt it to the new S905X2 and S922X.
I hope that when the S922X is out, your amazing Coreelec version or the Emueelec branch find a home there