OK for high or low letter road, but street name in the balloons have a constant font size.
I suppose is default setting. I try again.

[3d_config]
disable_roadsign_navigation_mode=0 ; =0 [balloons] (name street in balloons); =1 [in street]
roadsign_always_framed=1 ; (1) always street name in the balloons
roadsign_bitmaps=1; 0 rectangle frame, 1 rounded rectangle frame