Hey Joe you don't even need scales if you get me some simple numbers I can get you some good info. Measure the length of each spring with weight on them as they sit on the vehicle now and give me the lengths of each spring. For the front it looks close to having everything there that will weigh it down (motor, hood, etc). For the rear you may need to add some weights to compensate for things like gas, tools/spares, and anything that is not yet on the buggy but will be. Pass me those numbers and we can figure the sprung weight per corner and start making some decisions on which springs to run.
You can send those springs back and get the right ones when the time comes, so you are not out the money. Stuart is cool about spring swapping and since those have never been run they are fine to swap out.