Ive never used a lead sled or any similar device. Im sure they work to some degree at least.
Our main interest is a solid rest that will allow for good shot placment. Also be able to follow
a running animal that might also be hit regardless of which direction and how far/fast he runs.
Our serious long range guns are either 30 or 338 cal using heavy bullets over very large powder charges.
Theres no way to completly avoid recoil even with 20# or heavier guns with muzzel brakes.
Weight and muzzel brakes do help however. Id sooner shoot a 20# 338 with a 300 gr bullet than a 10# 30/06
with a 180 gr bullet as far as felt recoil goes.