theoretically I have 50 iron keys and 5 magic keys. What better do you think the first use? and can combine 10i-1 m what you think?
Just use them all!
There is no intrinsic benefit of using one set before the other. They have the same available range of troops and the chances of getting anything won’t change based on your existing troops.
Be sure to notify us what you got 
Ok I’ll try not to forget ^^:grin:
Ok I write until I remember used 60 Iron keys
Common 110
Rare 55
Ultra Rare 11
Epic 3
Legendary 1
Epic and Legendary: Shadow Hunter, Sunweaver, Dark Song, Behemot
Total Souls 1625
For My 
Fany Score 
Not bad you got a legendary