You will probably have to unload the forks. Either lift the bike via a front lift that uses a pin in the head tube or suspend the frame from something. With weight on the front wheel / forks you will likely not get the top triple clamp off without a lot of force and probably some damage. I used a Powerstands front stand with a pin that goes into the bottom of the steering tube to lift the bike. Then after loosening everything I used some light blows from a rubber mallet on the top triple clamp to remove it. If you are going to use a front stand, you will also have to use a rear stand to properly stabilize the bike.
I think you mean putting the stand's pin in the hole in the bottom of the lower triple clamp, right? Not the "head tube"?
I've seen pictures of some folks using a folding ladder to straddle the front of the bike then using ratcheting tie down straps hooked to the frame and attached to the top of the ladder. It wouldn't be my first choice, but in a pinch it may be an option.
I've successfully used a heat lamp to apply some heat to things that have been stuck. The lamp needs to be a few inches from whatever it is you're heating up, and it needs to be on there for a good 45 minutes or so. However great care must be taken anytime heat is applied to anything ... wires, grips, plastic stuff ... none of that likes heat. So use best judgement.
Never quit, die falling forward.