I only have two single stage presses. When producing a batch of stab crimped 450b loads, I do all the cartridges one pass at a time. IE charge a case, reach over to the press and seat the bullet. Set that cartridge in its appropriate row and column in my loading tray and repeat until all the cartridges are charged and their bullets seated. Then I set up one press for the initial taper crimp and the one beside it for the stab crimp. I then run through all the seated bullet cartridges until done. That speeds along pretty well. I used to reapply a lesser taper crimp after the stab crimp, but have found that if I don't, the little bit of induced mouth flare from the stab crimp does not make them hang up during feeding.
However the second taper crimp causes the stab crimp to relax ever so slightly, apparently from pushing down on the case to induce the repeat second taper. Its hard to find the words to precisely describe that interaction between the two, but I digress (my middle name). Anyway, when I'm zipping through the mass crimping portion of the routine, it really slows down the process when I have to put the necessary number of stacked shim washers on and catch them when I slide the finished crimped round out because I forgot to slide them back over the top. More times than I care to admit, that also involves crawling around in the floor trying to find where they rolled off to. To eliminate that speed bump, I have made multiple, custom length, modded Lee FCD's for the more popular crimp locations and depths that I use. They're not that expensive, especially if you catch a sale and you can get them shipped in the same box, without additional charge. I still have my set of shim washers and occasionally use them when experimenting with a new load idea that none of my custom cut ones fits. To each they're own... In the case of a progressive press, having to deal with the shim washer(s) would negate the benefit of the progressive aspect. I don't have the need for a progressive press as I rarely produce enough volume of a single load to pay off the investment in time saved. The modded Lee FCD dies will outlast me, so the one time investment in several of them, is worth the up front cost and lastly, it removes the need to remember which number shim washers to use with a particular load recipe. I number my washers in order of ascending thickness with
Micro-Dots similar to tracking how many times brass is reloaded. I have two of every thickness shim washer, each pair twice the thickness of the previous pair, so they're numbered: 1&1, 2&2, 3&3, etc. In my load recipe log, from back when I only used one modded Lee FCD, a recipe might call for 1,1,2 or 1,2,2 or 3 only, etc. I'm getting help from a therapist these days and just switch dies.
For someone who is content to just change shim washers, that Lee 45 Colt die would be the way to go. Its still a PITA grinding down the crimp with jaws to just right. I your brass hasn't been annealed adequately, it take a much sharper jaw to impart a narrower indentation in the bullet after the indentation propagates through the outside and inside walls of the case. Ever look at someone standing on a trampoline? The impression from their narrow feet is much more dispersed on the lower side of the surface they are stand on. Same thing is happening inside the stab crimped cases. More pressure isn't the solution. You just wind up imparting a figure 8 distortion to the bullet, depending upon its wall hardness and fill. That's why utilizing a cannelure or driving band groove plays well with the stab crimp. the indentation on the bullet is already formed, the it takes less effort and damage to the case getting the crease driven into the relieved bullet surface.
There I went again. Another page from War and Peace on a simple subject.
Believe it or not, I'm generally a quiet passenger on a long trip in the car.
Hoot
I 've been using taper crimpers for most of my straight walled cartridges forever.
Lots of very good information, but NO location or availability. 
