I find any extra wide yoyo to grind well, like the stampede and the n5. I’ve never used a steam, but many people say it’s a great grinding yoyo. The n5, even with it’s horrible finish, can outgrind my Cascade.
I’ve found that the yoyos that offer the best grinds fall into these categories:
*blast finish - Blasted finishes will increase grind time a little.
*weight - Weight usually contributes to spin power, which contributes to grind time.
*organic shape - Organic shapes are easier to control on the curve or your arm for arm grinds. Some other shapes will stray off course or not grip as well, especially when transitioning.
*raised rims - Yoyos with raised rims will reduce friction on arm and palm grinds because less of the yoyo’s surface is touching you, which means a reduction in loss of spin power and longer grind time.
I would recommend the SPYY Punchline Repeater to you. It has a very smooth bead blasted finish, a good weight at 67.5 grams, and an organic shape with raised rims. It is mid/undersized. It has an inner rim for thumb grinds. The only grind it doesn’t do is a true finger spin, because of the spiked hub. You can do finger spins with multiple fingers or fingers and thumb in the cup, taking care to avoid the spike. You can do off-axis finger spins. However, the signature SPYY spike does allow for matador play. Guy Wright had a lot of grind tricks in his trick repertoire when the Punchline came out, so I think that says something about it’s abilities as well. The older model Punchlines had lighter weights. I think they seemed to have more of a “floaty” feel, but you would be sacrificing a little weight.
Stampede is perfect for grinding.
As far as undersized try something from C3 or Werrd