It’s rather time consuming, wasteful of building materials and punishing to try out different base designs.
It would be great if there was a Base Defense Sandbox Mode, that works just like regular defense waves, except there would be no rewards, no drops, and no net loss of building materials. Ammo consumption and other consumables would still be in effect. Walls and such would get destroyed, but at the end of the attacks the materials would re-appear in inventory.
This would add a whole new level of game play in the designing and testing bases, before committing those designs in actual defense modes.
PS - I love this game!