Understanding the correct fittings for EK Matrix 7

As the title says i'm looking to understand the correct fittings for doing an EK Matrix 7 build. From what i've seen in videos, some people use the extenders and i can't figure out how i'll be able to understand if i need extenders, right angle fittings etc and i can't figure out which ones i need without needing to make any bends in my tubing. Is there a way to figure this out correctly? Because the last thing i want to do is buy all the fittings and then find out they are slightly too short or don't allign with my distro plates etc.

Looking at doing a Z790, 13900k, RTX 4080 strix build in a PC O11-D-XL ROG case with the distro plate.

How does one measure that they will need extenders when working out their fittings? Is there an easy way to achieve this? Apologies if this has been asked a billion times before. As you can probably tell its my first WC build lol.