yafc VS FactoryPlanner

Using a planner like YAFC, Foreman, Helmod, and Factory Planner is highly recommended. Also, the following mods are recommended for a megabase needed to finish a high-multiplier game:

It's not a website but try YAFC. It's the best planner for Py.

Planning tools/mods come in many shapes and sizes. I personally like Helmod but it took a while to learn it. There is also Factory Planner. Or external tools like Foreman or YAFC.

YAFC

Its called YAFC. Although it could use some fixes still.

Use an external planning tool like YAFC

There is a mod for that, and a mod for that, and a website for that, and another website for that, and a standalone application for that for big modpacks like Seablock and Py

You might also appreciate YAFC.

(Or you can just use a site like factoriolab or a mod like factory planner to do the math for you and have perfect ratios anyway. The only wrong way to play is whatever way you don't find fun.)

Use Factory Planner to figure this kind of stuff out. https://mods.factorio.com/mod/factoryplanner

SE has quite complex recpies, especially for space science and processing of the new ores. I would have stopped playing a long time ago if it hadn't been for planner mods like Factory Planner ( https://mods.factorio.com/mod/factoryplanner ). I found Helmod's interface to be rather complicated so I mostly use Factory Planner even though I keep both around (Helmod provides some additional options like planning your build around the amount of available ingredients or number of crafting machines). With the "matrix solver" feature, you can plan a factory layout that produces the amount of materials you need and takes care of most/all byproducts. This makes the process of planning fun instead of tedious and then putting it in action and watching your new factory section go brrrrrr as it produces a new shiny thing for you to enjoy feels very rewarding.

Using a planner like YAFC, Foreman, Helmod, and Factory Planner is highly recommended. Also, the following mods are recommended for a megabase needed to finish a high-multiplier game:

FactoryPlanner or Helmod - Helps designing production chains. Quite complex at start, but well worth it. Factory Planner is the newer and cleaner design.

Factory planner. This mod allows you to plan out the production before hand (makes making everything pretty way easier as you know how many machines are needed)

Secondarily, you could use a mod like Helmod and/or Factory Planner to help you figure out how to make items. These mods are better focused for chains - i.e. breaking down an item (e.g. a science pack) down into smaller parts (e.g. ores), but they can also serve the function of letting you know which machine to use for which recipe.

I personally use the Factory Planner mod because it has some nice in-game features like automatic blueprints from the calculation.