Now I'm not trying to second guess you here and I'm an admitted noob....but it seems the Belleville washers would be counter productive on the bolts. They would provide constant pressure if tightened enough to keep the bolts from moving around wouldn't they? There's no difference between them and a split lock washer is there? I thought that's why you didn't want a split lock washer.
To me this is a lot like your solution for the keeping the way adjuster in place. The way the old lead screw adjustment worked was to put back pressure against the clamping pressure of the single screw. But it also caused an uneven angle of pressure. So in my pea brain it seems the bolt heads need to be captured in the cap of the takeup nut, or some kind of compression washer like the Bellville in between the cap and body of the takeup nut. But that might mean it has to be different thickness to get the fit right. And still would need a solution for keeping the bolts from backing out. That's why the striplock appeals to me.
Or am I just like my avatar, just blowing steam and getting nowhere?