I ALWAYS wait to have ALL legendary ingredients.
Why risk having half the bonus if it doesn't hit successfully?
Ratio is 1 legendary to 2 epics and it continues exponentially down the line when it comes to chance of success.
No, chances are "50%"
I would wait to get all three legendary debris and then create the item.
That's my opinion, and most other's I would presume.
Thank you so much plarium suport gave me a similar response ill paste it
Plarium Support Team
Dear Jarl,
Thank you for your message. If chances of getting a certain type of Equipment in the Forge is less than 100%, e.g. 50% of Legendary and 50% of Epic type, it means that you can get either Legendary or Epic type of the Equipment. In this case, the probability of crafting a Legendary Equipment is equal to Epic but there are no guarantees that you will receive the Legendary type of Equipment after crafting.
You need to achieve the 100% probability for the certain type of Equipment in order to get it.
Do not hesitate to get in touch with us if you have other questions.
Best regards,
Your Plarium Support Team
Mee said:
That's my opinion, and most other's I would presume.
Well, in the past, when i was little, for normal gear, i have sometime take the risk... more unlucky that lucky
But for stronghold gear who cost a lot of mat, i don't... and certainly not for shaman gear who ask plenty of mat... same a 30% epic and 70% legendary is not worth the risk for shaman gear...
I agree with ANESFAN, when i started play in vikings war of clan, i took risks a few times and I was unlucky.
Now I ALWAYS take all 3 legendary material bcz it take a long time to farm every legendary material and i very disapointing when i get epic item from this
P.S. this is called Russian roulette 
This is even worse that Russian roulette, because when you have a mix of multiple qualities, each lower quality amounts for twice the level above. examples :
