Last night post-work I went to the hardware store and picked up a piece of aluminum angle for making a jig to drill the holes in the forms that I need to do. The jig is so I can drill the holes repeatably and in the same place for all the pieces. I'm gonna end up with five forms instead of the six I had planned, unless I cut another bottom piece from some 3/4" stock I have, which I will likely do anyway.
My plan is to be pouring the first stone mix into these forms this weekend. That will depend a bit on whether we're shooting: last I heard we were planning to shoot this weekend, but I haven't heard any specifics yet. That means tonight will be machining up the jig, drilling and countersinking holes in the melamine, and most likely ripping and cutting the last base piece for the sixth form. That's a lot for one night with everything else I have to do, but it leaves the end pieces remaining. I don't think I'll be cutting them, but I might depending on how well they attach. The end pieces are square and are designed to provide stability for when the forms are set up for pouring, to hold them upright and allow them to fit together in a bank. That provides strength and makes it easier to pour the bunch at one time.
Yes, I'm spending a lot of time with these forms, but they're intended to be used several times and I want to make them strong enough to be reused without having to rebuild them each and every time. Spending the time up front to make them sturdy and accurate is a good investment.