Part placement efficiency

As discussed here: Organism Building Feature Thrive won’t be going the spore route of having parts you can place (I’m not 100% certain but very close). So instead you gradually shape your creature. So you will be making decisions like “do I want to add 10% more cells to the leg muscles or brain”. That makes it a bit difficult to have a mode where you can test your creature as you could only afterwards revert it to how it was when you started. So this way you can lead your species into an evolutionary dead end.