Where is the best mounting point for these? Traditional line, center, or somewhere in between?

i have a pair of the original 185 roses huge (white/black/red, no rocker) under small marker dukes and 305mm bs radiums and ghosts. 5'9", 170lbs w/o gear, very aggressive and fast style, many years on the hill. originally mounted on the freeride mark (rear line) and found the ski to be balanced and natural feeling, with round tracking in the arc of the turn. when porpoising in colorado powder however the somewhat blunt tips tended to decelerate the ski when they plowed back into the snow, causing a lurching forward sensation that undermined my confidence in going wfo. later i remounted 20mm rearward of the fr line (quite alot fyi) and the change in weighting and float angle of the ski transformed the huge into a much more predictable and confidence inspiring ride in deeper powder. -20 resulted in a loss of nimbleness and precision, and upset the balance of the ski in most every day conditions though. i settled on -10 (not afraid to drill the boards!) and feel this was adequate to improve the powder performance yet retain the balance and all roundedness. these wood and metal boards proved to be excellent daily drivers in the higher moisture content and wind affected snows of the open swiss alps than in the lighter snows and tighter trees of colorado and utah.