Hi Richard.
With a shotgun close is good enough both in shooting and reloading, I don't see a need to weigh every powder charge. MEC bushings are notorious for dropping light, weigh the charge from a bushing until you get close to what you are looking for and then just load shells with it. (btw I use the 32 bushing for 19gr of RD too).
MEC charge bars often throw light as well, especially when 1 1/8 ounce and less are used with hunting sized shot, they are made for target size shot. If they throw a little light I don't worry about it, remember it's a shotgun not a rifle.
I don't use over the shot cards with folded crimps. Often times anything over the shot column has the tendency to open the pattern. I suggest you adjust the filler wad under the shot as needed to achieve a proper crimp. Eric's idea of putting the OS card on top of the filler wad is a better idea if you need to raise the shot column up a hair. Over time you will develop an "eye" for it and you will see that the shot column is either too high or too low to crimp properly after dropping the shot and looking at the shell prior to crimping. When I see a variance I take the shell out of process, either dump a little shot out if too high or pour all the shot out and add a little more filler to bring it up if too low. (A little piece of a cheerio makes great filler material).
The days of insuring a specific wad pressure are gone, all you need to do is be sure that wad is seated on top of the powder without any gap.
Because of small inconsistencies in materials and lack of precision in my calibrated eyeball I get an occasional variance in crimp depth, not much and nothing that affects performance but one can see a small difference here and there. I have noticed that when loading other gauges that don't use a filler wad there will be variances here and there as well even though everything is the same. It's the nature of shotshell reloading, the short ten is a little trickier in this regard because of a filler wad.
Bottom line having my Short Ten shells look uniform is a lot less important to me than having them perform uniformly.
Good luck and have fun, Short Ten's are a blast.
P.S. Paul mentioned hulls buckling. Sometimes hulls will buckle even if the shot column is the right height. If you find shells buckle just above the brass when you apply the crimp with a good shot height, stop and adjust the cam until they no longer buckle. The adjustment is easy, if they are buckling move the adjustment a little bit clockwise. You will need an allen wrench to loosen the set screw before you can adjust it. Remington hulls seem to be more prone to this than Federal hulls.
https://www.ballisticproducts.com/bp...ust/mecadj.htm