I have never used them before as i use two honrby H&M 2000 controller and a H&M 4000 R/H add-on for my layout which have 2amps output and my layout is 20ft 9" but the upper level will make 21ft but is only 6ft 6" wide.
I don't think there is any handheld controllers with alot of amps output not any that i have seen.Maybe some other members may know of any that have more amps output.