I'm not a taxi, but I have had a couple of deer done. Freeze drying is not a fast process. It is dependent largely on the size of the rack and the quality of the chamber. Hopefully yours will require at least 9 mos to fully dry, lol. Mine took about 5-6 mos to fully dry.
Obviously you need to handle them with care after the shot. My taxi did not drain the blood but first froze them. Then he caped and cut the skull and then put them back in the freezer. They will keep fine for a while if frozen but it is best to get them into the chamber as soon as you can. If the tag is required to be attached to the horns, tie the tag around the base between the burr and the skull with some galvanized wire, baking string, or a zip tie so the velvet is not matted down from attaching the tag. (Bailing/tie wire will rust pretty quickly if exposed to blood and rust is hard to remove.)
When they are done, they look just like the day you shot them. I was supprised at how light they were. It makes sense because all of the moisture has been removed but the weight was not what I was expecting when I first held them. The velvet is really durable and there is absolutely no smell. BOHNTR informed me that you can officially measure a freeze dried rack after the perscribed "drying time" has been met after removal from the chamber without any disqualifications.
You are most likely aware of this, but just a reminder that if you drive, be sure to fill out any paperwork at the ports of entry for states requiring an affidavit to properly posess the horns/meat outside of the state in which the animal was taken. You don't need any legal troubles with the buck of a lifetime.
Obviously you will have your punchlist done ahead of time. These are just a few of the things I have picked up in my experiences if you go the freeze dried route.
Good luck on your draw.