Well there is a compromise situation we often run here at club or regional level but not the Nationals. That is to have a ~1/3 MOA white square sitting ~ 2 MOA above the centre. It's invisible to sling shooters but gives the F boys something more definitive to shoot at. The original reason for putting it there was to still have a visible aiming point when the guts had been shot out of the target.One of the premises of having hospital targets, and keeping all targets in the air until all firing is complete, is to give each and every shooter the same 'presentation', and equal opportunity to do something silly like crossfire. Having separate sling and F target faces would be counter to that basic concept. And unless you think the range/facility is going to magically swap out targets for sling and F-class shooters and/or relays - which would be even more of a PITA now with so many ranges going to e-targets... I don't see a practical way to make it work. As much as it sucks to try and shoot with a high magnification scope on black target center, it's way worse to try and shoot on a light target center with iron sights.