As long as they're not in velvet, its not too bad.
Just a thought, before you split them, make a few small cuts, perpendicular to the main cut so you (or the taxidermist) can line them up later.
If they're in velvet, and you want to save it (like I did) the best bet is to have them mounted locally.
I went on an early season (Last week of August) hunt a few years ago in Quebec. I shot a nice double shoveled bull in velvet. I had researched the field care, had bought my formaldahyde & syringe and did everything they said to do.
We UPS'ed the horns, two capes, and some extra baggage from Montreal and took the meat with us on the plane.
Long story short, the package sat in USFW for almost a week and arrived a stinking mass of maggots. All the velvet and one of the capes were ruined.
The horns stunk to high heaven but after 5 coats of Kilz and some stain, they looked almost normal- and the cape made it, barely.
I would advise, if you want a shoulder mount, to bring back an extra cape if you can shoot two.
At camp,
On the wall: