The head (if I interpret your question correctly) is maybe 2 1/2" wide verses the bolt being maybe 1".... much smaller target. I DID initially start cutting on the head (of the bolt) but after so much grinding and so little progress, decided to cut the bolt instead.
Well, were it 'just' that simple....
I had a pipe wrench on it. Pipe wrench (with a 5' cheater bar) was about 18" in length ....the pipe wrench bent and then snapped in half.
I had a 1/2" impact on it (using 1 11/16 socket) and it was just being laughed at. I did about a full can over a month of PB blaster and... I forget name of other stuff... anyway, another can of other penetrating oil. I had my MAP gas on it trying to heat it. (I don't have anything hotter)
Laughed at
I borrowed my brother in laws 1" impact
Laughed at
Finally after spending maybe 3-4 hours on the SINGLE bolt (some of them DID come loose by the way with the 1/2" impact)
Anyway after spending quite a bit of time and just exhausting myself on it..... the nut rounded off so, I politely said "the heck with it, I'll cut the darn thing off" (<<--highly cleaned up for public consumption)
In hindsight, I wish that the couple that fought back at me would have just been cut immediately. Would have saved me SEVERAL hours of just shear persistence.....
But, persistence is what finally got them off!