The Chemical is called "Antler in velvet tan". I am a Taxidermist and you have to do more than just inject the antlers. You have to first make some small holes in the tips of the antlers so when you inject them the blood in the veins has a place to go. Then when you inject them you need to make sure you catch the main arteries and push the blood out with the chemical. Then you can brush it on the outside with the chemical, then you need to hang them until dry. Make sure they dry in an area that there is good cross ventilation to dry. It is important that when drying there is plenty of air circulation. or you run the risk of loosing them. I personally like to mix formaldehyde with "Antler in velvet tan". I get better results with that mix. And yes formaldehyde is very dangerous!! I wear a full resperator and face mask and rubber gloves and long sleeve shirt and protect every place. If you poke yourself with it is not cool!! As for a good taxidermist where do you live? and maybe I can help.
I hope that helps and good luck!!!