I just recently had a shot out of brush (50-60% lie). I had 60 yds. to the flag and 15 mph tailwind. I took off 3 yds. for the wind. I used the formula - 60 yds. x 1.45 = 87 yds. I used a punch shot with my 60 Wedge (84 yds.). I rolled right up to the hole.
I left the green dot where it was for almost full topspin.
This kind of shot will only work if you have fairway in front of you and you can roll it up to the green. There is no way to get good height out of the brush.
For light brush (30-40% lie), I use distance x 1.25. For brush (40-50% lie) i use distance x 1.35.
You might want to set up a practice round and purposely hit into the brush to experiment with this. You can keep taking a mulligan till you get a feel for how your clubs work with the balls you normally use.
I hope this helps!