Onc. leaf thickness? Some succulent-like, some very thin.

[alaskagirl]

This may seem like a weird question, but...

I grow mainly Oncidiums. Some of them have very small pseudobulbs with thick/succulent-like leaves (Hwra. Lava Burst & Onc. Carnival Costume), and others have large pseudobulbs with thin, flexible leaves (Onc. Sharry Baby & Onc. Twinkle). Is there a certain term for these differences? I seem to do much better with the thicker succulent-type leaved Onc's than others. I would like to get more of these in my collection but don't know what to look for!

Anybody have any advice???