I found the Griego give a bigger (fatter, wider) than Bach (I used to use a 1 1/4gm).
Some of this could also be attributed to it feeling more secure and stable; it feels like there is just more metal / denser.
In the meanwhile, I had the opportunity to try and compare the Griego 1, Griego 0.75 and the Griego 0.5 all in Deco Blank.
I can't provide long term experiences, but here is my impression after about a week:
The feeling while playing on any of them was good, but I could feel more resistance than on the Bach (1-1/4 GM). For me the 0.5 is too large. I did feel good on it, but I was loosing focus in any register. I also had difficulties to play in higher registers and I couldn't keep the tones in tune. Everything was too low. I also thought I would get a real monster in lower registers, but due to the size, I just got a wider sound that also lacked in focus. I think this Mouthpiece is too big for me, right now.
After that, I concentrated on the 0.75 and the 1 and compared them with the Bach. When I played with the Bach, I always thought, I was able to play louder with it compared to the Griegos. I also recorded myself (only on an iPhone, but anyway) and listened to it. This confused me, as I always thought, I was so much louder on the Bach, but the recordings on the Griego had a more stable and a sound that was edging out less. In my opinion, the effect was a bit different than, I expected. As the Bach was edging out more and the Griego didn't, it provided a better sound in the end. It was fatter, a bit darker and much more richer (which they proclaimed on the Griego Webpage). I also tried different registers, different volumes and recorded it. On the recordings there seemed to be just minimal differences in sound volume whereas, I always thought that, I played louder on the Bach. But from a certain volume on, the Bach just edges out the sound gets widespread, whereas the Griego still keeps its shape and rich colorful character.
I was also switching between the 0.75 and 1 and also came to the conclusion that the 0.75 is too big for me right now. On the recordings the Giego 1 was more compact in comparision to the 0.75. In the end, I cam to the conclusion that the Griego 1 could be interesting for me.
There are pro's and con's with all of the MPs. A definite pro is the rich and colorful sound. Compared to it the Bach sounds kind of dull. Also a pro is the stability it provides. As I described above it doesn't edge out too much. It also sounds thicker. If this is a pro or a con is probobly just a matter of preference. A con for me was, that it has a relatively high resistance. Instread, the Bach is wide open. You definitely need more air to play it louder and while playing it appeared to me that I have to play much louder than on the Bach to get the same sound volume, but the recordings showed it differently. To me this is also a con.
I will have to spend more time with it to get used to it and hope, I do so, because, I love the richness of the sound. Do you guys give a mouthpiece a try for several weeks to finally say yes or no, or is the first impression the best impression for you and you don't test any mouthpiece if it doesn't feel absolutely right the first time you play on it?
I am still confused about the sound volume differences I hear and "feel" while playing. But luckily it is not noticeable too much on my recordings. This is strange, but might come from the effect that the Bach edges out more and the Griego is more stable. Somebody else said in this thread that a more centered sound is louder. Maybe it is the same here!?