Finding regularity in irregular Spanish verbs

I found an interesting pdf yesterday that readers who know Spanish may want to take a look at. It's been devised to teach Spanish students how to conjugate both regular and irregular verbs, upon the assumption that even irregular verbs for the most part conjugate regularly, just in a more complicated fashion.

The main chart for people to follow looks like this:

You'll have to open that image in a new window to see it. I'll go through the steps one by one though.

First step is to watch out for these verbs:

The verbs this is talking about are the following:

If that's the case, then go to paragraphs 12 to 15.

Next up is to look for these verbs:

To properly use these verbs you need to learn about their diphthongization. dormir to duermo, etc.

Next step: does the root end in a vowel? If that's so and it's a 2nd or 3rd conjugation verb then go to paragraph 11, and if it's 1st conjugation with a -iar or -uar ending, go to paragraph 9.

and...after that the chart gets a bit more complicated so I'll leave the rest of it to those that actually know or want to perfect their Spanish verbs. What this document reminds me of is this post and this site, which demonstrate techniques to identify grammatical gender in French, which students usually assume to be irregular. French grammatical gender, like many irregular verbs, is fairly irregularly regular. That is, it's regular on a deeper level than simply looking at the final letter as one can usually do with languages like Spanish, Bulgarian, Latvian, and the rest.

It would be interesting to get input from a fluent Portuguese speaker on this too, to find out whether a Portuguese version of this chart and document would be feasible as well.