Tom wrote 
Would there be any benefit to using the"blue wrench," since the bolts
are attached to the shaft, rather than to the flywheel which would be
heated?

Tom

the heat from the torch could damage the main bearings if not used with restraint. I would hit the bolts hard with a hammer.  then with the flywheel locked try turning the bolts with a braker bar 

Bob

http://www.bostonengine.com