I was running at a very slow Z rate, so I was able to kick it up to 8 mm/sec and still seems to be working quite well.
I have just a little bit of deflection where I see that a couple of bearings are just shy of touching the horizontal rails. I tried to tighten things up more but then I was losing steps big time in the horizontal direction when using a step down of .4mm and a moderate speed for X/Y. So I loosened it up again for now. The end result doesn’t appear to be impacted by what I was seeing, but it shouldn’t have that deflection. I may need to wait for the rest of my new steppers to arrive before I try tightening it up again so I have more drive power.
But the good news is that backing off the tension a bit again and I was back to working quite well. And Z is much peppier now:)