Unless you run a buggy I would be surprised if there is an acre an hour difference betwen a 17 1_2 and 25 foot head,less if there is alot of roadwork involved. Watched a guy with a massive machine,must have been a 35 foot haed in a 30 acre field in SW Ontario. lots of overlapping and partial swaths. Could have been done alot quicker with a smaller machine and much less fuelwise. Rates are anywhere between 35 and 45 for wheat here. Even that is cheap at $1.20 a litre for fuel,and rising