Ideal settings for Lower Thirds clips

What is the ideal spec for a lower thirds clip?

To be a lower third. Simply divide your frame height to 3 and place elements in relation to that line so to emphasize it and let the upper space mostly frree.

I have seen one contributor use 1920x300 pixels as lower thirds. Is this acceptable? I believe I already have inventory saved at something like that. originally intended for the VJ crowd.

Yes, it is. But only on Pond5. It is called multimedia format. Other sites accept only standard resolutions(not to be confused with SD).

Well since I don't sell on any other stock footage site but Pond5 that works for me :)

Is it also customary to have PNGs as the root image format when saving to .MOVs? I think some others have said that will preserve the alpha channel. By the way thanks for answering my questions.

I highly recommend using Animation codec. It has better, much better quality compared to PNG. I know there is a trade between size and quality but is worth the price. You are welcome anytime!

Make sure on the Animation codec that you change your color depth to "Millions of colors +" to include the alpha channel info.

What are the standard resolutions? There are so many to choose from. Would that just be 640x480, 720x480, 800x600, 1280x720, 1280x960, 1920x1080, 1920x1200, 1920x1440?

Thanks for answering most of my questions.

Are there any specs for 2k, 3k, 4k, etc formatted videos for the lower thirds animations? For instance I am finishing out a set of 2400 fractal flame loops at 2400x600. These were originally intended for triple wide monitors for VJs. But could this also be considered a type of "multimedia" lower thirds for a display resolution of 2400x1800 (if such a machine exists)?