Thank you both for your comments.

First, I found the manual ( with help from my wife).

It's not one covered by the recall (113.196321), and sounds similar to yours, Dave. The adjustment screws you mention are the ones I referred to in my post, and are good.

right angle arms - this seems the best place to start- again. I've been fighting them for quite a while, but it may work best to have the table front tilted a up a little, and at least get good 90s. Will have to see how far off the rest gets.

the table is flat according to both edges of my straightedge, but lacking enough straightedges to compare to, I can only surmise that the longest I have is, indeed, straight (a man with only one watch always knows what time it is, a man with two watches is never sure).

I think I'm to the point of starting over from scratch, step-by-stepping it through the manual to find what tweak I overlooked.

Thank you both, again, for your productive comments.