It would be so nice to have an ingame calculator, so you can choose the optimal machine without making the mats for every single item.
for example:
you have a button on left upper corner (like other mods do) to open a window with the calculator.
in this window you can choose an item, and then it gives all possible results you could do (including modules) to have the optimum/maximum CS possible .

i hope you know what i mean english is not my native language

Thanks for your suggestion.

But there are some other concerns about introducing in-game GUI, mainly about UPS-friendly and mulitplayer compatibility. (Or maybe just I am not experienced enough in using the API.)
I have to think more thoroughly on how to do that. Because adding new items and entities of machines is simple, but creating a new GUI is much more complex than it sounds.

For the moment, it will be quickest if pre-calculating some quick-reference of minimum recipe times, like the tables in FAQ. I will expand these tables for some typical combination of modules (like 4× Prod 3, 4× Spd 3, 4× Prod 3 + Spd 3 beacon(s), ...) when I have time.

I have updated the tables in FAQ. You may use them as quick-reference.

Current 0.17 experimental game is still quite buggy. (For example, 0.17.5 makes most of my 0.16.51 megabase save game unloadable.) So I am hesitant to add any new features at the moment, no matter this in-game calculator or for my other mods.

I have found a mod Actual Craft Times Remade featuring ingame calculator for production machines. It supports most (except for lab overtiers) machines of this mod, and provides a direct and clean interface to display the needed values. It also supports speed and productivity effects from modules and beacons.
Hope you will find it useful.

thank you very much for this info i'll give it a try