I have also used your method and to date it is the easiest in terms
of picking up materials.
>repousse using heavy duty alum barbecue foil
>prepare design on another piece of paper
>tag board pieces covered with a thick coat of white glue
>wrapped carefully in foil
>carve immediately before the glue dried
>when the glue is dried, the design is supported by the dried glue
>cover with india ink,
>wipe immediately with tissue, let dry and then buffed with steel wool.