I can view em move at the same magnification as I viewed my soil samples with - 20x eyepiece, 40x objective.
This is what they look like at 60x:
View attachment 180258
At 800x, they look like monsters from some mid 90s PC game
EDIT: according to this paper: http://www.doiserbia.nb.rs/img/doi/0354-4664/2007/0354-46640701081P.pdf they max out at 210 micrometers long
Ya two spotted mites are double that size.