I tested out the sample and hold IC's and they work just as I expected. However, I also had a realization that might explain why some of my previous attempts at a real latch failed. I had been testing them by hooking up the input wires to the three voltage rails, moving them from rail to rail, and watching the output on a meter. In testing the combinational circuits I've built this always worked just fine. When I started making sequential circuits I ran into trouble with unexplainable outputs that didn't match what I thought they ought to output. I knew that when I moved an input wire from one rail to another there was a period in between when there was no input voltage and I always accounted for this. Unfortunately I always thought of this "input" as being 0, just like in a binary system. Not so here! No voltage input is actually equivalent to a - input because - is the lowest possible input. All that time I was confused by inexplicable outputs, but the outputs I was expecting were wrong to begin with. I wonder how many of my previous latch designs were actually working perfectly...