FAST combat new style or old skool Big Iron , Raunchy, VooDoo, Equalizer, or all others with inside wing BC.....
Most competitive Fast Big Block combat is flown with foam wings and top side BC and fuel cuts... yes there is/ are lot of East Europe made ARFs with internal controls
Top side BCs are usually best with Buttons and line lengths in regulation Eyelet to eyelet of 60' +/-6"
In my opinion old skool for nostalgie craft that might not ever see for than 50 flights ever...who cares....
we have plenty of historical facts that aluminum or nylon Bell cranks do NOT cut the solid or stranded lead-outs....rather the Bell Crank or Horns wear and do get sloppy...crap there dozens of photos of this wear here on SH in the Brett Buck sandwich Bell Crank threads
on the other hand the effort and practice to make the lead out to Bell Crank interface most long lived and least drag...copper tube and 7 strand stainless .037 with adjustable guides is not hard to fabricate