This is the amount of conduits I crafted to get the exact one I wanted. So stop complaining and get grinding. 
More often that not, you can work with a different suffix on Conduits and shift some resists around some other way whether that be via different armour augments or swapping around components, for non-mastery relics getting a completion bonus to a resistance to cover yours or something else, different MI affixes etc…
You don’t have to copy a build 100%. You can make tweaks depending on your circumstances.
I mean, if you want to craft them without save roll back, it’s not easy. But still nothing close to finding greens with desired affixes. And as Stupid Dragon said, a lot of resists are interchangeable. I think if you are unlucky it’s gonna take you 5-10 hours to farm for for one Conduit. But that’s like nothing considering you get the exact core build item you want.
Crafting conduit can be difficult task. First you need to hit the correct skill modifier and then to have useful resistance. But in FG you have so many augments that any form of resistances can usually do the job. But then again hitting the prefix you want is 1/9 chance. When I crafted NB amulet, always received Blade trap one 
So l learned to save my character before craft conduits/relic. But then again you can just use 3 party software for that purpose. So you have multiple choices like every RPG game…