Metric modulation with tuplets?

Hello,

How would you input metric modulations like the examples below (examples are from the Chapter 23: Metric Modulation – The Rhythm and Meter Compendium)?
(I think using arrows like ← old = new → would be better)




The Metrico font can do all of these (with the possible exception of the comma):

For correct playback of complex relationships, you will have to calculate the resulting tempo and hide a metronome mark.