Went through the same set of worries on my G/s with pushrod seals, went with the above wrench. I read all about the heat gun.
Someone, Bless their soul, piped in to put the wrench in place with the lug in place and just start up the engine. I did, and the wrench nearly fell of it's own weight to loosen the nut.
Before I could not budge the thing... Your results may vary of course, but you've got the bike right there and it knows how to get hot on it's own.