Recommended amount of orbs for summoning on new Legendary Banner?

If you're happy with any red/green/blue it's worthwhile. I would just go for one 5 star and stop though as I hate leaving unused pity rates. If you want 2 of 3 in red/blue and 3 of 3 in green then it's a better banner than average to summon on.

Ur good dude. If u get bad luck tho...u get bad luck. But 100 usually does it (to get A hero....not sure about multiples tho)

139 should be enough + you get a couple more till the banner ends if you have bad luck. I got 7 in 600, so ~85 orbs per 5*.

139 is plenty if you want to get 5* units, I managed to get lucky with 2 in 30 orbs.

As for what color is the best? In my opinion:
Green>>>red>blue=colorless

I've started pulling until the first 5* for legendary banners. You know it'll be unit you want then accept your luck is done. I spent 80 orbs and got 2 Brave Ikes in the last circle, would've preferred 1 Hector but the game won't allow me to have new legends.

Spent ~120 and got 2*L!Ike, 1*Leif, 1* New Hector... i'm sniping red/ green