I think that you've found that it's not really important which method you use. Any are better than what you were doing. You most certainly were in the majority that shoot several inches too long because of not knowing any better.

Draw length is a very personal matter, but getting close to what you should shoot helps keep body parts in line, which helps accuracy a heap. Personally I use the wingspan method, and then get bows that are draw length adjustable. There are several reasons for this. First, bows are put toether at the factory and shipped to the dealer. Not many have the string/cable twisted so as to put the bow in proper specs, including the draw length. Therefore, few bows really come off the rack set to the length they are marked (bottom limb tag), and most are long. That's why it's important, when buying a bow, to have the draw length actually measured and/or adjusted on the bow you intend to buy.

Secondly, very few bowhunters know how or what is meant buy an optimum draw length. This meaning adjusting the length down to last 1/8" or so. There are reasons for being this picky, which takes time and experience to learn, and the desire to do so. This is also a reason I hardly ever recommend buying a bow that is draw length specific, such as what you are looking at.

Let's face it. You shot a bow that was several inches too long for how many years? Now you find that out. But what if you buy a $700+ bow that is not adjustable and find it still doesn't fit. Well, now you're stuck with it or paying a lot of money to buy a new cam and possibly the string/cables to match. We're talking about maybe $150 more.

I've been shooting and bowhunting over 35 years. I get a new bow every year. I know that my draw length is 27" plus or minus an 1/8", depending on the bow, and I refuse to buy a bow that is draw length specific.

By the way, it's easier to sell a bow that is adjustable, too, should you ever want to upgrade again.

These are just some of my thoughts on the subject.