The briggs is on a tapered shaft, so it has the whole taper lock thing working against you.
The Victa flywheel is on a parallel shaft.
Give the two screw drivers thing a go. Just be careful, slow and steady wins the race.
If it has been sitting outside without the pullstart/cowling on it it can be corroded in under the cup which will make the job a lot more difficult.
If not a puller the same as above is easy to make. I would think that the Victa flywheel also has holes in it ready to be tapped at 1/4 unc. (probably whitworth actually)
A word of warning on the tapping. You can damage the thread with a soft faced (typically brass or copper) hammer, even with a plastic one. Take care. If you put the nut on and use a regular hammer you can also damage the thread if you do not take care. The thread is whitworth and a thread die will cost you about $80 or more, so its best not to damage the thread.
You would only tap lightly on the shaft while loading the flywheel up from underneath with screwdrivers or tyre levers.
Do not be afraid to load it up with peneatrene or WD40 or whatever and walk away. If it takes days, thats better than the red mist coming down and it turning into instant scrap metal.
