Are the Griego Artist 1 and Greg Black NY 1 technically the same size as a small bass trombone mouthpiece? I’m just curious as to why they’re considered tenor mouthpieces and not small

Bass mouthpieces?

I’m sure there are other examples but I can’t think of them off the top of my head!

No. They are tenor trombone mouthpieces.

You can add the Bousfield and Doug Eliott XT106 (with tenor cups) to your list.

The cups are various tenor trombone depths - none of them are as deep as a 2G or 1.5G. Some players have found that larger rim diameters work better for them. While some of these are bigger than what's been offered in the past, some manufacturers have always had some larger diameter mouthpieces in their tenor trombone offerings (including in small shanks) - Bach 3 and Schilke 53 for instance. Most of these new ones are only a size or so bigger in diameter. If it works for you, great! If not, play something else.

Jim Scott

They're very silly mouthpieces, but they are still tenor only. I've tried an Alessi 2 on bass (which imo is nearly unplayable on tenor) and it was still not a real bass sound.

As a primary bass trombone player, a Griego 1C is amazing for me on tenor. Too shallow for bass and sounds terrible.

The NY 1 rim size lives in an interesting category (~1.5g rim dia). I know tenor players that play this rim size and larger (27.5mm) with great success, although it's certainly outside of the norm. Then of course there are many bass players on a 27ish mm rim with different cup specs that also find great success. I've played around with designing mouthpieces this size, and found that while taking a tenor mpc with this rim and using it on bass proved less than fruitful, the opposite (using a bass mpc with this rim size on tenor) proved highly useful for some bass players who double.

I actually keep a 27mm with one of my deeper bass cup depths and .310 throat in my case for occasions where I have to play parts that are written on the higher side, or even a tenor part. Its just easier to drive for longer than my normal bass mpcs (29.25 and 29.5mm rims).