Narrow boards on Domino

[ear3]

What's the narrowest board you would feel comfortable mortising with Domino and trim stop?  I ask because I was going to build a mission style stool, which has all of these narrow slats.  I think I've mortised a 1 3/4 piece before, but this looks like it calls for something closer to 1 1/4 on the slats.

UPDATE: Though I see on this one, they actually cheated and inserted the slats as a separate unit, probably using nails to secure slats to top and bottom cross pieces rather than mortise and tenon -- but I'm still curious as to the minimum width someone would do with Domino.

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[tiralie]

16mm/5/8"

 

[dltflt]

I done as small as 1".

 

[ear3]

Thanks.