If any VFD is going to work for a HUD in the day it's going to be the tiny one (K610a).. it's several times brighter than all their other displays because each pixel is directly driven.

It is really, really tiny though.. before ordering one I would strongly suggest you print out a screengrab of the Empeg display at 39.3 x 9.7mm and put it where you want in your car and see if you can read the display without squinting and staring at it (always a good idea when driving).

Ooh, no, you're right. I just posted where I didn't think it had a command like this, and you bring that up. Thanks.
It's still not AS highly optimized as sending jule 4096 woth of info (still goitta send headers) but it's somewhat better than 4 frames.

The headers are only 6 bytes, 0.15% overhead, vs drawing pixels, 300% overhead.. The K610a being only 19,200bps ( = 4.6fps unoptimized ) is far more significant.