Ok, this is maybe way out there, but:
Say I complete my first deer mount, Maybe the thing looks ok ....but suppose the thing is hideous. Can I rehydrate the whole head, tear it down, clean the form and start over from scratch or am I pretty much gonna have to look at the crappy attempt for the rest of my days as is. Or, where do beginner taxidermists send their first attempts that turn out looking like some sick burro with horns? Is there a special destination for these? How about my mother-in-law's livingroom?

So what did you do with the skin ? did you tan it or Dry preserve ?

Pratice pratice and pratice some more. As you complete each phase check it out if it is ok then move on.Before you even start make sure everthing fits.

Rich

http://www.rgswildlifetaxidermy.com

wet tanned

With a tanned skin you might be able to rehydrate and mount but, your main problem will be the face, as if it has memorized the shape of the manikin , you won't be able to shape it to a new manikin.

When I have done it i use the same manikin and then alter it a bit to improve muscles and veins and then use hide glue real heavy and reglue the face so it picks up all the deatils.