Wobbly,
At the end of a long and frustrating day with only a short time available to consider use of the program is probably not the best way to approach it. Although I haven’t seen it, the program offered by Neels Vannik is apparently a derivation of, and extension of, the Blair technology (which I have seen) and is likely as good as you are going to find at modelling gas dynamics. It may not be easy to digest at first but you need to sit back with an open mind and spend some time absorbing the overall approach that it uses. Come to grips with what it offers and how to use it. It is much more sophisticated and capable than Dynomation.
And do not expect to get instant, simply obtained, answers. There is a reason that Dynomation doesn’t do a good job of gas dynamics analysis.
There are any number of testimonials for the successful use of the program, including rddreams (just above, #2893) which, if you read through it, uses the Vannik program.