I have more than 40 mini/double hooping tutorials on my website. All free.
They posted the intro on YouTube. It's a little cheesy. :)
The DVD is good if you're a complete minis beginner. It literally begins with: this is how you spin a mini on your hand. Some of the techniques and tips are really helpful. I found the practice drills helpful. I got it because I'm just kind of into having a library of hoop DVDs as a resource and haven't worked with minis much. (I have all of Hoopnoticas DVDs, Hoop Technique and Home of Poi's beginner poi DVD is on the way, plus I've got Betty Hoops' DVD too... I should get HoopGirl's...). It's got some cool basic tricks in it though.
A good size for mini hoops is probably anywhere between 18-26 inches. I think the average is 22-24. Hoopnotica has a new minis DVD that's $20 and starts with some really basic moves and Home of Poi has a beginner poi DVD that's only like $6 or $7 but I'm not sure how it would transition to hoops (I ordered one last week). I haven't taken any of SaFire's online classes but have heard great things about them. I've also used some of HoopDeeDoo's tutorials.
When I first started hooping I didn't think I'd ever have an interest in minis, but now that I'm getting into them I love it. I can only do a few moves so far (chase weave, windmill, and what Hoopnotica calls flag pole; I'm working on thread the needle, three-beat weave). Anyway, it's why I ended up ordering a set of flag poi too. I feel like learning both will give me more room to play and practice. :)