Please help! Wanna learn how to make glass night lites :)

[CraftyNewbie]

Hey guys. I'm a hobbyist and I saw these awesome glass fused night lights... I really want to learn how to do these. I have a place where I can go to use a kiln but I need to know a couple things first...

1) I want to use broken wine and beer bottle glass and I dont know if you can round out the sharp edge's in a rotating tumbler without shattering the small pieces or turning them to dust. Should I sand them?
2) How do i keep the glass from completely melding together with the back piece of glass so that it had a 3dimensional shape and doesn't loose the shape of the small glass pieces.. do i fire it at a low temp, for longer? I just want it all to be connected but keep each pieces shape
3) I should lay out the design first on a flat piece of back glass, fire it, and the slump it? so the top chunks of glass dont slide right? and..
4) Approx. what times and temps should I fire them at?

Anything you guys know about how to do this would be GREATLY appreciated!!! I'm really dead set on learning this and you guys are the best people to ask, so please.. ANY info is all new knowledge to me Thanks you guys!!

ps- in case the pic doesnt show up it a pic of an Iris Night Light by Reborn Glass.. you can view them at VivaTerra.com If you can please look at the picture so you know what I'm trying to accomplish thanks again!