Request for clarification about the ad sizes:
"Whereas the current initiatives only allow for right sidebar ads (300x250), the new initiative will also allow users to submit banner ads (728x90)"
The "current" rule that was listed in your (JNat's) post on all of the non-beta sites for the 2020 community ads says:
"The image that you create must be 300 x 250 pixels, or double that if high DPI."
which means that (600 x 500) is okay too. On [Chem.SE](Community Promotion Ads — 2020Chem.SE) 100% of the 10 ads used the (600 x 500) size, and 7 out of 8 ads on [Phys.SE](Community Promotion Ads — 2020Phys.SE) did.
I suppose that the ads that actually get shown on the right-side of the screen, end up only being (300 x 250) anyway, but it's useful to be able to show them as (600 x 500) when running these ads for election in Meta. Is it correct that the (600 x 500) option was only for running the ads for election in Meta (not for the actual ads as they appear anywhere) and that we would still have the option to post them in (600 x 500) format when running them for election?