I got my answer from Reggie!

"Dear Megan,
My general response to any lettering is not to squeeze letters between the lines. Iusually prefer to pierce through them--more freedom.
But the historical models aren't in front of me so I could be sending you in the wrong direction there.

I would definately spend more time on words and quotes- especially anything familiar and I like. It helps build directness and rhythm-and keeps yoy interested.

Lastly, and very importantly, take any piece you do and hold it up to a window so the back side of the paper is facing you. This truely helps you to see your work with new eyes: very important if you are hard pressed for good critical input. One last idea. In copying any hand, make a photocopy with red toner of the hand you are copying at the size you want to practice it at---on a transparency. After practicing the hand on paper with black ink, superimpose the transparency atop your letteri
ng. Imperfections of letterforms nd spacing will jump out at you.

Good luck, Reggie"

It's a little generic, since i'm doing a specific quote that is supposed to be 'illegible' but he has a point that I can follow up on once I've done what Meisterin Helene suggested.
I'm using quadrants (long diamonds) at the top of my M and Ns, and bottom of Us. The quote uses diamonds with the ticks - and they form that extra bit of line to join the strokes to form those letters.
I've always used both quadrants and diamonds in forming the letters. I'm pretty sure that this is the normal way of writing Gothic Textura Quadrata. But the quote doesn't do this. I know that the Bedford Hours script does use quadrants.
I could say 'enough already - I've got heaps better at spacing between the verticals and straight verticals and that was the whole point of the exercise" but I want to get this dratted thing perfect. So I'll change my ductus a little.

One thought that I had last night was to slow down my writing even more, and produce no stroke unless it's perfect. No ragged edges on a diamond that then gets hiddden by a vertical line, no vertical lines that are pretty straight but has one edge a bit ragged, nothing. Not that I'll be able to do that consistently yet, but that's what I'm going to aim for. If I can get straight lines and diamonds absolutely perfect then mastering the rest of the gothic script should be relatively easy. And it goes towards pen control skill as well. And don't you dare call me a perfectionist! :-)

I have heaps to type up on Script Analysis. Just gotta sit down and do it. I've already produced a draft ductus! Maybe tonight. There's a limit to how long you can spend trying to produce perfect lines in Gothic scripts. Sitting up but kind of hunched over the work at the same time to be over the top of it, gripping the pen and going sloooow. It hurts after awhile!