my guess is that assuming the board is accurately measured at the range (Some are not) and the fact your using range balls, if your landing at 200 id go with +10% ish so around 220 carry. I know this time of year on soft parkland courses im only getting around 10 yards of roll (well thats what it looks like from the tee) but in the summer this could triple if not more.
The only real way to check, is to go a practice ground, hit 5/10 balls and then measure the distance, iphone has a free app called my caddie pro which has a shot measurement facility included. you wont be able to work out roll, but your know your exact carry distances, with good balls.
Also remember balls fly better in warm air, so i reckon 200 carry and stop in the winter will be more like 240/250 in the summer months.
