I glued the PVC pipes for the blade unit and even painted it all black. I needed some way to cover the blades, mostly to prevent accidents. Not likely these little blades will be throwing rocks around. I found some plant saucers on Amazon that looked like they could do the job. The problem is how best to attach them. I bought some aluminum strips and decided to bolt them together. Some cutting, drilling and bolting and I made a nice little cover for the blades. Bought some u-bolts to attach the cover to the PVC pipe, which is going to require just a little more drilling.
I went back and re-installed the big handle to raise and lower the blades and re-purposed some of the mechanism used to lift the original deck. Instead of four offset lift points, I now have just two parallel to each other. The last job is to figure out how to connect the whole blade unit to these lift points. It needs to be offset to give some overlap in the blade paths so that there aren’t uncut stripes in the grass. Also hope the whole arrangement is flexible to handle a bit of collision but not so flexible that the blades move around in normal use. Almost there.