I have suggested this to YouTube identities, such as GeoShifter, that this little experiment has some merit. It's very easy and takes very little time. Simply go into your backyard, put on a pair of arc welder's goggles or mask and observe the Sun. All glare and peripheral rays are removed and the Sun is observed as a green disc. The greenish colour is due to the filter of the goggles/mask and can easily be adjusted in Photoshop or similar.
The observed Sun using this method looks remarkable similar in size to the Moon. Funny that You might also use a filter made from this material for your camera. Bright light sources during the day are 'quelled' and other strange light phenomena can be observed particularly if you use 'night mode (IR)'. I would also recommend using a 'welder's goggle filter' while performing day time time-lapse photography. I've not used this methos myself, but hope to very soon.
Good luck in your endeavours proving the Flat Earth.