Please first ask yourself "Why is your goal "reducing iso"?" Are u trying to reduce the footprint of windows? Or is it completely experimental?
1) You can use "Lite" preset in the components page.
2) You can set to "Custom" on updates page.
3) You can ReUseDriverCache on drivers page.
4) You can remove the languages and drivers you don't need on components page if its not removed completely by Lite preset.
5) On Apply Page, Select For ESD Compression and Remove NonEssantialEditions, like all of them.
And i can assure you, this will be the smallest size you will ever get. But as every windows shared on internet in named as "performance edition, lite, super duber perfect windows etc clown shows", this one will be the same. I mean NonUpdatable, and will most likely have lots of compatibility issues since you will be removing nearly everything, without checking for what your softwares will need...
So your goal shouldn't be slimming down windows to the bones, your goal should catch functinal windows without the things you don't need. It takes LOTS of tries untill you find your own configuration. We can share ours, but it is not meant for you, its for our usage style.