Questions and clarifications regarding WCAG SC 1.4.4 Resize Text

Hi all,

We are looking for some clarification regarding WCAG SC 1.4.4 Resize Text, specifically the following items:


  1.
SC 1.4.4 Resize Text has this blurb about behavior above 200% scaling:

Content satisfies the Success Criterion if it can be scaled up to 200%, that is, up to twice the width and height. Authors may support scaling beyond that limit, however, as scaling becomes more extreme, adaptive layouts may introduce usability problems. For example, words may be too wide to fit into the horizontal space available to them, causing them to be truncated; layout constraints may cause text to overlap with other content when it is scaled larger; or only one word of a sentence may fit on each line, causing the sentence to be displayed as a vertical column of text that is difficult to read.
          
The working group feels that 200% is a reasonable accommodation that can support a wide range of designs and layouts, and complements older screen magnifiers that provide a minimum magnification of 200%. Above 200%, zoom (which resizes text, images, and layout regions and creates a larger canvas that may require both horizontal and vertical scrolling) may be more effective than text resizing. Assistive technology dedicated to zoom support would usually be used in such a situation and may provide better accessibility than attempts by the author to support the user directly.

We want to know more about the right way to be compliant with regards to scaling beyond 200%.

Does this blurb mean it's really okay if a web application is unusable beyond 200% text scaling?
Is the recommendation beyond 200% for the app to still be usable, but okay if it looks bad visually? What is the official recommendation for text scaling beyond 200%?

  2.
On iOS, their larger text settings actually scale up tone the font-size property of the text, while Android's larger font size settings make the text appear larger, but don't scale up that property. Furthermore, iOS larger text settings can go way beyond 200% while Android's larger font size settings are capped at 200%.

In your eyes, is iOS doing the right thing, or Android?
Have you heard of web apps trying to meet this success criterion struggling with cross-platform support?

  3.
We found a way of making font size scaling behavior consistent across iOS and Android for web apps, and we want to hear your take on it:

We tie the device's font size setting to the initial-scale property of the viewport meta tag<https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag>. For example, if the device's setting is to 200%, the initial-scale property would be set to 2, 150% to 1.5, etc. What we accomplish here is zooming in the page such that the text is the size specified in the settings.

Thanks!
Alonso