None of them are very easy to set the right angle. You have to loosen the bolt, set the angle, then tighten the bolt without moving the angle. Not really hard, but it can be annoying if it moves while tightening.
The trick is to check the angle again after tightening.
The Miles Gilbert has the best design because you can set both angles before you start grinding. It's on sale at Midway right now for $35.
I like the look of the Graco better, but I haven't used it:
I use a sanding jig purchased from Brownells that is similar to the ones shown above. I changed out all the screws to socket head to make it easier to work with. I also turned two thick washers that are a tight fit with the screws and have a shoulder that sticks out and fits tightly into the holes of the recoil pad. This way you only have to smug the bolts and the pad is held firmly in place. You do not get any distortion with the soft pads. I do not freeze any of them, no need to. I use a protactor from a combination square set to match the angles on the stock and transfer to the jig. Good luck. Bob
After a bit of a conversation with Joe Beary (www.gunsmithertools.com) and realized that with his jig the combination square was unnecessary. This makes things a little easier to deal with. It is a few more dollars than the Gilbert Miles, but not by much.
You won't be dissapointed in the ease of this fixture. You can grind a pad in a very short time. The nice part about it is that the pad is always mounted with the solid part of the pad on the fixture. You don't have to worry about tightening it down too tight and deforming the pad when you grind it.
The trick with soft pads like Gooey is to use a more coarse sanding belt/disc for the initial shape. If you use too fine a grit it tends to pull at the rubber rather than cut it. I only go to the fine grit when at the finish stage. This is more for the plastic to get it nice and shiny. That step is not necessary, but it looks much more professional that way.
Andybull above has the best pad grinding set-up. Just need to mount the vertical bar w/ hook onto the sander so that the pad lines up at the middle of the sander. You can move pad side to side to use all of the belt and the angle is perfect every time as the whole thing will keep rotating around in a circle so that you can grind the whole pad in a 360 circle no problem. Good for adj. butt plates as well. Break-em all. Jeff
My new jig showed up today (ordered on the 3rd. Great service Joe!), and it appears to be as good as promised. I can't wait to give it a try! It has a nice set of instructions, complete with pic's, to help out a newbie like me. I'm really looking forward to learning a new trick.