'removeHidden' mode will thrash your CPU, take ages, and may crash the browser. Start values low, work up.
Scaling ratios
A3 (1-up): 1.0000
A4 (2-up): 0.7071
A5 (4-up): 0.5000
A6 (8-up): 0.3536
A7 (16-up): 0.2500
A8 (32-up): 0.1768
A9 (64-up): 0.1250

So if 100 lines looks
good as 1-up set it
to 70 at 2-up 50 at
4-up, and 35 at 8-up