Glad that my reply was helpful!
Interesting that you mentioned the thumbrest and I’m glad you reminded me about it. This can be a big issue as far as the right hand. I have small hands myself, and have always struggled with hole positions – especially the left hand ring finger (watch out for straining that!), and the thumbrest position vs the first finger of the right hand. If your thumbrest is too far down on the recorder, it makes you bend your wrist some to cover the first hole. If it is too far up on the recorder, it makes you reach to cover the bottom holes.
I recommend you get a clip-on thumbrest like this:
They seem to be hard to find as an add-on item (you get one with a new Yamaha or Aulos instrument). This will allow you to experiment for the best position.
Some folks play without a thumb rest (especially Europeans, it seems). I have never been able to do it. Regardless, you have to put your thumb somewhere and not move it, so whether you have a rest there or not, it doesn’t really matter.
As far as the new Zen-on G-1A, well, I can see why it has gotten mixed reviews. I think it is dreadful. I was VERY disappointed in it, after all the hype about the holes being refined with tapering, etc. To me, it sounds very poor, clogs easily, etc. In fact, I went out and bought a NEW 1500 after seeing how bad the G-1A is. The 1500 is pretty nice, I think, so you have yourself a good alto to start with (and continue with too; most modern plastic recorders are good enough for any level, really).
The Ecodear is VERY unique sounding (and pretty too!), with a very narrow windway. I think the regular Yamaha 300-series altos, and the Aulos 509B (“Symphony”) are better for beginners.
Anyway, good luck with the recorder. Be careful, though – don’t hurt your hand; take a break if it starts to hurt!! 🙂