Real Spellers

It is a great question Lisa!
I'm quite confident in identifying twin bases in Latin. I know a fair bit of how to analyze Latin structure, and identify if we have evidence of a twin. I'm better at Latin verbs than anything else. So I know that <scribe> and <script> are twins.
When I go to Etymonline and find the Latin root scribere can go to LatDict to find the four principle parts of this verb:

scribo, scribere, scripsi, scriptus

And then I show the infinitive suffix in the second part this way scib(ere) and analyze the supine suffix in the fourth part this way script(us).

When I see that the spelling of what is left is not the same, I have evidence for my twin base in English <scribe> / <script>. I know that there is a final <e> in <scribe> of course from the word <scribe> itself.

But just being in this etymological family does not make a twin. The fact that the word word <scribble> goes back to this same root does not mean we have a triplet!

So the fact that <dyne> and <dynam> share a Greek root is not enough information to conclude we have a twin. I need to learn more about Greek structure before I will be able to come to that kind of conclusion. Perhaps others out there can help us with this process. Until then, though, I'm very happy to say that these bases are in the same etymological family. I don't have the need to go deeper than than yet. One day I'll learn how to -- maybe your question will be the spark for me to finally gain control of that understanding!