Welcome, welcome, welcome to the thread! Grab a chair,
a hammer and let's have fun, LOL!
With regard to vibratory tumblers, I do not have one, nor have
I ever used one, but hopefully someone will be along to chime
in with experience.
It is my understanding the vibratory tumblers
do not give the rounded shapes most of us seek when tumbling
glass. The rotarys, other than having O-ring slippage once in a while,
can be left unattended, while the vibratory require checking to make
certain water level remains consistent. The vibratory style are also,
for some, much noisier.
As for the water, yes, it is required, though I'm no expert. It just
seems the water is a necessary component to imitate the ground of
the ocean floor. If the glass tumbled naked with only grit, I think you
would end up just tumbling glass naked with grit. LOL.
At present, I have some pieces of glass tumbling which are as large as
1" x 2" thick. No doubt you could use larger pieces, as long as they allowed
movement of the piece and distribution of the sand / gravel / whatever
grit-like material you choose to use.
Again, I'm no expert, so I look forward to others chiming in.
:-) Karen Marie
P.S. Glad to see more interested in this fun hobby!