What's the best way of going about getting a unit to +10?

I think people just spend a lot of money.

its 200k feathers to make 10 4-stars into 5-stars to add onto the base 5-star unit and noy accounting for the 2k feathers each time the unit is pulled as a 3-star depending on who it is.

9 times out of 10 whales just wait for a focus banner and pull them as 5-stars to start

Well to get a 5 star +10 unit all you have to do is spend loads of real, hard earned money (or your parent's money I guess :P) and just spam summons when the hero you want is featured.

OR.... you can just save up 4 star units and make them a +10!!! I have a 4 star +10 Nino, and that alone is pretty damn good. Basically a +10 4 star unit is the same as a +5 5 star unit, which is still hard as fuck to get, where as many 4 stars are rather common.

So, your choice, spends buttloads of money and pray to the fire emblem gods for the right summons.... or you can just make +10 4 star units lol

My purely feather graded el nino!

My first of such.