How much space is between each shelf

The distance between each shelf is 10.5-inches.

How much weight can each shelf support?

Each shelf can support up to 10-pounds.

since the distance,from the floor to the bottom shelf is 32.5 inches. What's the distance from floor to the second shelf and to the third shelf?

The distance between the remaining shelves is 10.5-inches, so the floor to second shelf is 43-inches and approximately 54-inches from the floor to the third shelf.

What size are the screws needed. My package didn't have enough for completion and I need to order more

I apologize for the delay. Here is what we found:

Head diameter: 11mm Bolt diameter: 6mm Bolt length:28mm

How high off the floor is the support bar and is it adjustable? How high off the floor is the first shelf?

The distance from the floor to the bottom of the bar on the back of the shelving unit is 7-1/4-inches. And the distance from the floor to the bottom shelf on the unit is 32.5-inches. Hope that helps.

What size and type of screwdriver is needed to assemble?

The screw size is - Part J: Truss head,Philips recess screws(1/4''x 20 x 1 1/8'')