After a lot of trial and error, I have a solid set of wheels. I just wanted to post a pic and share what I learned:
1: scooter wheels are necessary - I tried using 9" mountain board wheels at first, too heavy and bumpy. Luckily I located a tinker shop that gave me all the scooters he had for whatever donation I wanted. I got 4 scooters for $20 all told.
2: a little bit of grinding using a circular grinding bit allowed for a perfect fit of sealed bearings using 1" copper joining piece as a shim. Not the 1" copper tube, but the cap that fits two 1" pieces together, it is the perfect shim material for the bearings I got. I'm using the original axle bolts that came with the wheels and I cut aluminum spacers to fit between the bearings. Rock solid.
3: an incoming wave will throw you to the ground if you try to ride through it with wheels.

> an incoming wave will throw you to the ground if you try to ride through it with wheels.

Learned that one myself. It would require wide tires to skate through the surf or soft sand. Best to stick to the hard pack.

Looks like a fine set of skates! Welcome to kiteskating and hope to meet you out on a dry lake some day.