Joe, most people struggle with the Grand until that light in their head comes on and they fully comprehend how it works. And the most troubling thing seems to be getting the crimps nice without buckling the hulls. It was for me and I've heard that from many others.
The wad has to be seated low enough to allow good crimps but not low enough that it is compressed. As with most loaders that seat the wad at one station and drop the shot at another, if you compress the wad it will just spring back up before the weight of the shot is upon it. Just as you would select the best wad for your recipe and adjust your wad seating ram/shot drop tube on your MEC, you must use the right length wad and then tune the length of the lower shot drop tube on your Grand. The key to knowing when that length is correct is seeing how the shot gate moves.
Ask the great folks at RCBS for a long lower shot drop - in fact, I used a 20-gauge lower tube (the uppers are the same) so it couldn't catch on a wad petal - and a few extra knurled brass threaded spacers that go between the upper and lower drop tubes. Then, using the lower drop tube you now have, see if the shot gate can be pushed back by hand when the loader's operating handle is fully down. If so, your wad is not seated fully and the wad/shot column is too high. Add spacers until it bottoms rearward j-u-s-t before the handle stops moving down. Now you know how long the new lower drop tube must be with the normal one spacer.
If the shot gate is bottoming prematurely, you are compressing the wad which is springing back up and your wad/shot column is also too high but for a different reason. You now need to shorten that lower drop tube until the gate travels fully and just a hair more. Use your metallic shell case mouth deburring/chamfering tool or a file and a large drill bit to smooth your saw cut if necessary.
If you use two different powders and/or wads for your singles and handicap loads, for example, you'll either need a lower drop tube for each recipe or perhaps just add or subtract spacers when you change loads.
The Grand, in my opinion, is the nicest manually-operated loader out there. I only sold mine when my arthritis made even my Grand's butter-smooth operating handle painful to move due to the rotational movement required of my shoulder. Learn it and you'll love it.
Chuck, did you by chance buy mine? I sold it to a fellow poster on here and it was damaged in shipment. RCBS was kind enough to furnish the needed parts at no charge and spare him a lengthy battle with UPS, even though I had paid one of their shippers to pack it as well as ship it.