Bed glass flatness?

My Prusa i3v 10" bed doesn't come with glass.
They say get a piece at Lowe's/Home Depot.
Did that.
Homed and leveled bed as per directions.
I noticed that on first layer print nozzle is easily .4-.6 above the glass so .2mm of filament is dropping onto glass.
So I set Z home to the center height instead of XYZ home in right rear of bed.
When repetier Host starts the print it goes to XYZ home, then goes to center and prints. I was worried it was going to smack the glass at XYZ home, but it didn't and print started about .4-.6 above glass in center again!

Bad glass, sloppy Z adjust?
I can adjust the Z adjust by hand. Initially had to use the allen wrench.

I dont know the procedure you followed, but bed level with respect to the earth is unimportant. The bed needs to be "level" with the print head. You should home the head to several locations around the bed, and home Z only. then make sure you have equal distance between the head and the bed. Adjust bed level until all are the same distance, and then adjust the Z endstop until you get the distance you want.

That said, it's not unusual for there to be variances in the thickness of the glass, but those are usually compensated with slicer settings (first layer thickness, etc)

What you said is what I did. Sorry my version wasn't understood. Basically, I set Z height in the center of the bed instead of Home corner. I have springs at 3 corners to level the bed to the nozzle.
But, the center of the glass appears to be lower than the edges.

You need to make sure nozzle is same height off bed in all 4 corners. This is probably the most crucial step that many people let go with "that's good enough" only to struggle with their printer because of it. Google or Youtube 3D printer bed leveling to see the proper method.

I would bet that your glass is perfectly flat (same thickness all over) but you have not perfectly leveled the bed. If you fear running the nozzle into the glass then get the proper Borosilicate glass that can take a lot more abuse and thermal shock without breaking.