Really, I'd suggest for complete info, and the 'standards' used and defined for us 'citizen scientists', would be the
CoCoRaHS website, where precipitiation, evapotranspiration, (and other weather/climate goodies) are reported and monitored by numerous scientific and government agencies, including NOAA, etc Including the first nationwide attempt at
Ice Accretion standardization and reporting. Including videos, webinars, etc... etc...
Unfortunately, the absolute best way of reporting any of this stuff with any accuracy values, with consistency across the board, is still direct human observations... one extremely accurate electronic station does NOT mean that ALL are accurate, so the manual methods are requested... The questions, issues and thoughts you've expressed are well known, and thoroughly exploring the CCR site, materials, podcasts, videos, should just about cover anything you'd need, I think, from the point of view and abilities of us 'non-professionals'..
My 'snowcam' is NOT for 'official' measurements...all my measurements follow the CoCoRaHS protocols... that's about the only way to achieve standardization from a 'layman's perspective which can interface with the 'official' 'scientific' institutions, and the CCR observers are pretty much widely trusted and relied upon. My web pages are only 'quick looks', and 'reference'... CoCoRaHS "severe weather reports', and direct spotter reports direct to local WFO are best ways "Quick Info" to local WFO.. in fact, however, the NWS LMK WFO often calls the cam into their situation displays,
especially during event onset, and end, and for quick 'ground confirmation' of what they're observing, and inferring...
Hence my experiments for some time with 'visual' indication of Icing onset, rather than specific measurements... especially in night-time hours.... one of the meteorologists there and I've been 'playing' with this for several years. It's almost impossible to present reliably on camera, in a simple, inexpensive manner, in all situations and conditions, for many reasons. The intereseting thing about the WFO's... they LOVE the 'snowcams', and other weather dedicated cams... and more and more are used, when they are aware of them, and some of the specifics of location and site. A LOT of PWS cams are monitored in some fashion. Many of us are probably not aware of their usage... heh...
...and it doesn't matter to a great degree how fancy they are... mine only has all those overlays for the specific 'ice accretion' pilot currently ongoing... as long as they're of good quality, and have a snow stick and board in the image... they're aware of how 'approximate' that representation is.