IaNerd: thanks for posting that link. Re-reading my post I realised I'd made some mistakes. I've have now fixed them there and will explain here.
I initially gave the tuning the wrong name. It should be called Paddy-Richter Extended. Here it is over 10 holes:
CD. EG. AB. CD. EG. AB. CD. EG. AB. CD
I called it a Pentatonic tuning but strictly speaking it's not, because it has the 7th of the scale in there (B). A true major pentatonic would only have the 1-2-3-5-6 of the scale.
I guess you could call it a Hexatonic tuning. It's actually got two Hexatonic scales, C (first position) and G (second position):
CDEGAB - first position, pentatonic plus 7th
GABCDE - second position, pentatonic plus 4th
With the strict pentatonic scale, as with the standard major scale, you have the incongruity of an odd number of notes (5 in the pentatonic, 7 in the major scale) having to fit into the binary blow/draw pattern on the harmonica. Odd numbers are not divisible by 2, so something has to give: add a note, double a note, reverse the breathing pattern - those are the traditional solutions. In Paddy-Richter Extended I add a note, the 7th in the home scale of C, but here's how a true pentatonic tuning it would look with the other two solutions:
Double a Note
CD. EG. AC. CD. EG. AC. CD. EG. AC. CD
Reverse the Breathing Pattern (Circular Version)
CD. EG. AC. DE. GA. CD. EG. AC. DE. GA.
I haven't used either of these, but I do use a different doubled-note pentatonic scale with x-reed all-draw harps like the AsiaBend:
PowerPentatonic All-Draw Tuning
CD. EG. GA. CD. EG. GA. CD. EG. GA. CD
(In this case it's an all-draw harp, so the 'blow/draw' in each hole is replaced by 'slide out/slide in').
You can hear it here:
https://youtu.be/fjdlu2atodI
Triona, to answer your question: Yes that's correct for the key of D in Easy Third/Dale's Irish Tuning.
I think you asked a similar one in relation to another tuning somewhere else in the forum. The best way to think of tunings is as numbers of the scale. Therefore this tuning can be written as:
1-2. 3-4. 5-6. 1-2. 3-4. 5-6. repeated
Now it can easily be transposed to any key just by selecting the notes that correspond to those scale numbers.
This helps in playing as well. When I'm playing harp I never think of note names, only numbers in relation to my home note. That can be the key note of the tune, or the starting note of whatever position I'm in. It simplifies things a lot for swapping between harps in different keys.