Henry - you torque that bolt with a breaker bar - she will snap. I would suggest patience and moderation with the bolt - final choice is breaker bar and snap it off and drill and tap. But before you do that - remember that it is difficult for the penetrating oil to get to the threads. Letting it sit for a few days may not do it. I would suggest you soak the top of the bolt with the Aerokroil - and several times a day spray more on and tap the head of the bolt for a minute or two to set up vibrations to try and get the oil into the threads. If you repeat this several times a day for a few days - you might get lucky. If not - this is going to sound stupid, but it really can work - heat the bolt until it is warm enough to melt wax - not real hot - then rub a candle around the head to try and get the wax to flow into the threads. Let the bolt cool to air temperature - then try to remove. One last thing I have been experimenting with - You must have heard about CLR or other rust and mineral removers - they sell it to clean taps and sinks around the house. I had a severely corroded trunk lock assembly on a Jetta that the key would not turn in because the brass tumblers were corroded into the white metal cylinder. I put the lock assembly into CLR for about 1/2 hour and let it fizz. When I took it out it was black - I wire wheeled it and it cleaned right up - the tumblers were free! I dried it and lubed it and it still works 6 months later. As a last resort before using expreme breaker bar method - try soaking the bolt in CLR ( make a putty dam around the bolt to hold it on the bolt head - and don't forget to clean the oil off first so the water based product can get in) and let it sit for about an hour. Then try to remove the bolt. If that fails it is twist and pray and buy a drill bit and tap time.
Good luck - I know the frustration of corroded bolts. - Don't forget to put anti-seize on the bolt when you put it or a new one back in.