Low Profile Car Creeper

I wanted a car creeper after performing the biannual service on my jeep. It was December in Iowa and there was melted snow all over the garage floor. This car creeper is more or less a copy of what I found online. It's not any better than something you could purchase (probably much worse actually) but since purchasing a welder last year I find myself looking for ways to use it. The above picture looks like crap. I need to throw some paint at that thing but it was like -20F when I was putting it together. And for some reason some of the wheels looked like they are so crooked that only 2 would touch at a time. But the wheels look just fine in real life so why don't you just pretend that they look good in this picture too.

Steel Frame

The main frame is made of 0.75" rectangular steel tube with 0.125" wall thickness. It was galvanized surplus steel, so need to be careful not breathing in welding fumes. I wanted to use larger wheels (3 inchers) so in order to keep the height of my body low, the wheels would have to cantilever off the side of the creeper. This makes the creeper wider, but the creeper is more robust and can roll over debris with the larger wheels.

Wheels

The wheels are used surplus I picked up for $4 each. They are 3" plate caster wheels and can handle a ton of weight. The caster wheels are bolted on to the creeper in case I need to adjust the height of individual wheels. After getting everything all welded together one of the wheels was like 1/8" off the ground. Ended up being I welded one of the wheel mounts on incorrectly. After I ground that baby off and re-welded it all six wheels are touching. I was very surprised they came out so well.

Link to the initial design, I think ended up being very close to what I made.
Design01