I use a pair of these and haven’t managed to fog them up once whilst riding in all conditions.
https://www.rad8.co.uk/store/p46/Rad8_506_MTB_-_Photochromic.html
I bought a 30 quid meter from Wiggle which works fine. I had a run on busted spokes a few months back and couldn’t face wheeling the bike to the shop each time. So far all my replaced spokes are holding up... so no complaints.
LifeLine Spoke Tension Meter
Spoke Tension Meter
That signifies a speed sensor issue. Could be the sensor, wiring or magnet. Is the magnet still attached to the spoke (assuming it has a spoke magnet... my 19 Trance did.)
Probably time to get it back to the shop unfortunately.
Just set the stand up so all the weight is on the top hook with the bottom hook acting like a guide with a slight gap beneath the cables on the lower stay. That’s what I’ve done... works well.