Wow, thats a good base for a potentially useful tool.

I always had troubles to calculate exact numbers, so I've ended up by multiplying everything by 1000. In this regards, one improvement would be to be able to write number of turrets directly, maybe between (-) and (+), so I don't have to press (+) thousand of times

Hmm, thinking about it, I always wondered if I will have enough cargo for all these materials. Searching up the cargo size for each material and considering this in calculation, hmm, that was the hardest part and I wanted to have a such tool to help me out.

And I've noticed 2 things: one is Target Systems, which I sometimes add and are not in your fiddle, and second this is the credit cost of a turret (which could be an another number input for your math tool).