Long arms won't get you any more travel.
I am running 12" coilovers now, and the only thing limiting my downtravel is the shock length. I have a set of 14" coilovers going in this weekend, and even with those the only thing that will limit my down travel is the draglink I am currently running(Hits my sway bar link.)

 

You get a steeper angle on mid arms compared to a long arm witch in total will cause a bind or a limit in downward travel. Then if your talking the bushing in stock arms forget about it. That's why with a jk you can't go bigger than a 4.5 with a mid arm.

 

And I got my info from Chris at Evo because I was thinking of going that route and didn't want to drop 7 G's so I went with a mid arm first. I figured I'd change it out later and sell my mid arm.

 

I do have Adjustable Rock Krawler Upper and Lower Control arms if that makes any difference I'm not to good with suspension

 

I have 100% usable down travel with my metal cloak arms and 12" Radflo coilovers. Disconnecting the shocks nets me another few inches before anything else binds(Confirmed this when I pulled my axles to do some work on them.)
All this is from my first hand experience, everyone setups may vary.

 

Not meaning to hi jack but what's the advantage of coil overs

 

There's a guy in our club that has STOCK arms with enough lift to run 42's not sure on exact height but its over 4.5

 

Now tell me how you get as much travel as an Evo with Kings. No wonder you bottom out and don't bind. Your radflow a don't get a true 12" of travel.

 

And his caster is horrible and his jeep rides like sh-t on the road plus his pinion angle on his drive shafts. And prone to Death wobble. I never said you can't do it. You can put lipstick on a pig but it still don't make her a beauty queen.

 

12" of shock travel is 12" of shock travel no matter the brand.