The "Fred Sled" is a single shot DBM adapter for CF stocks with the metal DBM latch.

I beleive you have a CF blind magazine stock. So what you need is the SSS Single Shot Loading Ramp. There is a SA or LA ramp for centerfeed actions that fits like a glove. No need for modification with a CF action. Go to the Sharp Shooter Supply web site http://www.sharpshootersupply.com/ and look at the pictures.

I have also used the CF ramp in a SF action with some minor modifications. It's just slightly too long for a SF action. So file/grind/cut enough metal off the rear of the ramp so it will slide up into the rear of the SF magazine port. A drop or two of epoxy glue in the seam at the rear of the ramp will keep it in place.