Thank you Andreas, for your awesome, indepth feedback!! We will certainly implement some or all of your suggestions.

Regarding the volume/price dichotomy: I find that one complicated, but we might switch to two tabs: one price, one volume-based. Need some more thinking and experimenting from our side.

We're launching a new version next weekend, with range sliders instead of spinners, so it works on all devices.

Best for now, and good luck with your tool! I agree with your analysis about Nicosia, many things feel familiar but on the other hand, many other things pass by that seem tiny but are often quite fundamental and instructive as they point the way forward.