200yds is my max also. I practice shoot a-lot at 200 and have taken a handful of deer from 180-200yds. And they have to be relaxed and or feeding or standing still.
I prefer shots at 100yds and under, I wont bash anyone who shoots at whatever distance they want, they have to live with the outcome and sleepless nights waiting for it to get light to pick back up on the sign. But if the person practices at 300yds all the time and can put EVERY shot at 300 in a 4" circle and get the wind right EVERY time, then your the Man!
On the topic of the lead sled, I dont have one and cant comment, I use a pillow on a bench, then switch to shooting off just the bench, it's more like real life shooting.
(BP)