The .dac files are huge, no doubt (2-15 GB), and unwieldy, and that very likely explains the chart issue, but I ran into the obs point issue in the .fem file (which runs under 50 MB) before I ever ran the model.
I have set the time steps as large as I can (up to 180 days) in the ~90 year simulation, but I need to characterize the drawdown and recovery curves so I need all the time steps. Of course, I only need all the time steps for a relative handful of nodes, but there's no way to selectively limit the .dac file. If there was some way to export fluid rate budgets without going through the chart, this would only be one of a long parade of small annoyances.
My model is a bit over 1.4M elements and runs out in 250-300 time steps. Large model, but not unreasonably so. I'm running it on a dual six-core machine with 32 GB of RAM, so it ought to have the horsepower to do it.