SH bring up a good point, I had a 45 pound anchor on my last sled and it was bit much to pull up on a continuous basis. I have an elec. set up with the 55 pound (my wife bought it for me) so neither she or I have to pull it up. The 45 pound was as much as I would want to pull up throughout the day.
Easing on to the anchor also makes a big difference as to how well it bites.

Good luck

Doubletake