I have had some fun playing in DADGAD since you mentioned it. And planning to go and see Sarah McQuaid in November - her book is good too.

Here's a little no risk suggestion. I have no personal interest in recommending it I just think it is a brilliant resource which I only came across relatively recently. I like it enough to have subscribed to it - full streamed access to everything on it is about £10/$12 a month at the moment which I think is great value. Whether I use it or not now I've bought it is a different matter :) but...

It's Truefire and it has two Tony McManus Celtic guitar courses and a Pierre Benusan class on DADGAD. Each of them are really well resourced with tab - slow down - play along - etc etc and each are several hours worth of structured tuition

You can get a 30 day trial to All Access streaming for the princely sum of NOTHING. At least worth a lot. Back to planning what I am going to learn over the next year :)