Erik-
Kudos. I also am anticipating rollout as a spectrum analyzer is exactly what I need. I've tried RTL-SDR dongles and it doesn't give you a "big picture". Especially when we are going after interference that we find "walking up and down" the band. Same with CABLE leakage. and here in the US, that's a problem.
I also think you're conservative approach to the 2.8" vs 4" version is appropriate. I did buy a 2.8 NanoVNA then "had to have" a 4. I have used my 2.8" 10 times that of the 4".?? Because on the bench the 2.8" is attached 100% of the time now to a PC..? Being able to capture, view, store and print graphs plus using my mouse that I'm accustomed to after 20+ years of steering one. I'm happy.?? Both the 2.8 and 4.0 are hard to read in direct sunlight. cardboard boxes help. Who does not have a computer, tablet or smart phone for a bigger display these days?
Finally, although selfish, I would hope and I'm sure all on here would agree, that you allow your groups.io followers 1st crack at the release production run, as the second something new comes out, the pig herd (hams) will run out and want one and they can't even spell spectrum or analyzer. In the USA we have a comment regarding them, "more money than brains"? In any case they will deplete units on the shelf, then bombard? the group with stupid questions. The downside to your journey to fame and fortune.
Larry W8LM
ARRL Life Member - Licensed 54 years.?
Larry Macionski