Yes, your neck tension is about what I'd thought it would be. .004 to .005 is pretty high tension even without the extra thick necks, but with the .019 to .020 thick necks, it's like a vise grip. I'm sure this is where your pressure issues are from. It's quite typical for the wssm's.
For starters, start with an annealed piece of brass, then do the full "cam over" resize in your FL die. You've got to set those shoulders back, and get that brass softer. Then test chamber this piece of brass. It should go in with an easy bolt close at this point. If this is true, then proceed with the rest of the brass the same way. If it doesn't, then you're not getting that shoulder set back, and screw the FL die in further.
As for neck turning, once the brass is annealed, you don't need to take off much brass in the necks, say down to around .016 to .018. Bear in mind your chamber is cut for brass dimensions in the .020-.022 range. If you take off too much, then firing and resizing "works" the necks a bunch and your neck life will be short. If you anneal your brass every 2 to 3 firings, this will help your brass life. I went with bushing dies on my brass and used the bushings to set my neck tension. With the thick necks, I would not want any more than .002 tension in a sized neck (that's still gonna be on the tight side). That should be plenty of tension for bullet grip in the magazine and feeding, etc. You may even find that .001 works fine for you.
So, if you set your turned neck thickness to, say .018 for example, then:
.018 + .018 + .224 = .260
That's 2 thicknesses of neck diameter, for across both sides of the neck, and bullet diameter.
If you go with .002 for neck tension, then you'll want a bushing diameter of .258
I would go with .001 for neck tension myself, which would give you a bushing of .259
Either way, you'll want to pick up a couple of bushings on either side of your "target" diameter, just for tuning purposes, so you'll want .257, .258, .259, and .260
Bear in mind, as the brass hardens, from resizing and firing, you'll need to adjust your neck bushing size to compensate for the difference in tension. Thus you'll want to anneal your brass every 3 to 4 firings at the least. You should be able to "feel" the tension when you seat your bullet in the case.