Nice - this is the kind of mounting method I am giving a try on Grey Squirrels.
About using the skull:
Could you just dissolve all the flesh parts by suspending as much of it as you could? or even pop it out then dissolve all soft tissue and then just roll it back into the mask sleeve again?
I guess stuffing it full of chemicals and resin kinda makes sure there's nothing sinister gonna happen in there though

Will make sure to post some pictures - I will borrow a digital camera, or scan my photos, or use my mobile 'phone's camera.