The 94C draper head is built by Honey Bee, the auto float is an option and was not available initially. If you are looking for a used one, check to make sure it has that option. To have a dealer install it will cost you about $1,700 Canadian.
The 72C is a riged auger head that was built in Saskatoon at one time. It is usually half the price of a draper head from the factory. You might be able to find a good used one for about $15,000 - $20,000 for a 25ft. A 30ft will be a bit more.
Apart from the engine falling to bits there pretty good combines, iv had two now with bad vibration inside the engine, check all the studs on the fuel pump and the exhaust manifold to see if there all still there.
Check the chopper knives. Use wind knives on the very outside row and the run straight knives for the rest. Still get good chop and spread, eaiser on fuel and get alittle more usable hp out of unit. Check the engine wire harness for wire damage due to abrasive wire loom.
Fuel pump and exhaust manifold issues should have been adressed, so i wouldnt loose to much sleep over that, but check just incase.
They are a good machine and you will be happy with your purchase.