Re: Not putting in default values is fine, ...
For Http2MaxSettingsPerFrame, given the minimum value is 7 and maximum settings options are 6, I guess that means set it at the minimum or just above in case of future enhancements? Sounds dangerous if thats the case - surely IIS should set based on supported SETTINGS options and allow sites to overide if required
There's also Http2MaxSettingsPerMinute which seems friendlier - 7 x number of expected clients per minute and I assume bump up or down if you see issue. I would have thought MS could calculate a value based on CPU speed which could then be overridden by sites that needed to adjust it rather than leaving it as an exercise for the reader...