Improved Critical: Ray

After years, it finally happened: Some caster took the feat "improved critical: ray" which leads me to this question: How do I script it for spells? They can be configured to be melee or ranged attacks, melee or ranged touch attacks, but nowhere there's an option to set crit rate from 20 to 19-20 as I can for weapons. I could try "IFTAG: spell; keen" thanks to Kelrugem but I wonder if there's an easier, simpler way (I could go "IFTAG: ray; keen" but that'd require me to rewrite every single ray spell in the database to add "ray"as a tag)

And Merry X'mas to everybody!

I think the IFTAG: spell; keen is your best bet. A custom weapon that's used for Ray attacks might work, but it'd take away the potentially useful tags that'd normally be there and the chatbox wouldn't say what spell it's from