Yep, a steady pull is the best way to shift a Victa flywheel. Remember, they mount on a parallel shaft, so there's no taper lock to overcome. That requires impact!
But they can become rust-bound, if the mower has been left out in the weather.
As I'm fond of citing, the engineer's rule of thumb is that iron rust occupies seven times the volume of the metal from which it was formed...
I don't favour WD40 - it's not bad for displacing water, but it doesn't penetrate very well, and is a lousy lubricant.
CRC 5-56, Inox/Lanox, Penetrene, Castrol DWF are all far superior; so is a 50/50 mix of Acetone and Automatic Transmission Fluid.
A bit of heat [electric hot air gun - not flame] applied to the flywheel centre often helps, too.
I tend to make flywheel removal the first-up job, before the engine is removed from the chassis.