Yes, it is quite interesting trial.
Looking forward to see the progress.
Other way I am on the view of Glen: since it seems (comparing the face of the tin figure with the painting) that major modification should be carried out, the total rebuild would be more promising than modification of the present facial lines.
I think a Dremmel (Proxxon) powertool with fine chiseling head would be a help.
Good luck!
sandor