I'd forget the Sculpey even though it's giving you good impression
results. I think you're going to be disappointed with trying to deal
with the ash left over from a Sculpey burnout. And... the fumes as it
burns are probably not too great for your lungs if you're in the
vicinity. I think Sculpeys formula might be in the styrene family of
I'd try getting hold of some sculptors wax (like good'ole Victory
brown) and blend it with your injection wax. Victory Brown by itself
is very soft and sticky. Injection wax by itself is usually hard and
has a a fairly high viscosity unless super heated. Together the 2
waxes combined can make almost any consistency you want depending on
the proportions you use.
If your original can stand a little heat, you can warm it with a
hair dryer before applying the wax so the wax picks up the detail
before chilling. A very light coat of a silicone spray will help to
release the wax when cool.
Try to use a themometer for the wax mix temperature so you can
repeat the results.
I've used this technique before and used an inexpensive eye dropper
as the applicator mechanism.