Normally water is used with diamond saws. Can water be used with this? Want to immerse wheel in pan of water and use bottom of pan to guide stone to get parallel cut. 

I imagine this will be very messy. 

Will this hurt the EZ lock shaft????

What speed range should be used with this wheel? Description says not to go over 20000, but this doesnt agree with the speed guide.

The practice of drilling in a pan of water is common practice in jewelry and lapidary work as can be seen by the following quote from a jewelry workshop posting

"Put the stone in a container of water and drill the stone in the water. Whatever you do use water to reduce heat and cut down on dust which can be toxic in certain stones like Azurite because of its high copper content.

Use diamond coated drill bits with a rotary tool with a minimum rps of 20,000 rps if you can.
"

Using the diamond wheel in this case may not even be possible because of the "splatter".  I haven't tried it.