Those are some nice looking sets crappierascal. I made some of those a few weeks ago and they sank great. I made some molds out of 5 gallon buckets for the concrete and put the wood inside just like you have. You can reuse the buckets over without wasting them. I posted a picture of how I did it. I used duct tape to hold the forms together until the concrete set up then just pull them apart and off the concrete when they were set up. You can spread the bucket apart to get it off around the concrete. I also used them for some bamboo sets that I made a few weeks ago just don't use as much concrete about half. Just remember don't put the mold on a concrete slab like the one in your picture without putting something under it. Use card board or a piece of plywood. I did mine in my garage and they almost stuck to the exsisting floor
Just a thought if you don't want to waste your buckets.
Crappie X.