Tested with 100 PregeneratorMaxChunksPerTick and the server stops with the error:

[Server Watchdog/FATAL] [net.minecraft.server.dedicated.ServerHangWatchdog]: A single server tick took 60.00 seconds (should be max 0.05)

Obviously that's an insane number, but OTG should probably set it to safe levels if it detects the number is set too high in the OTG.ini

For v8_r2, have set the maximum to 5. I've not seen any improvement past 3 myself.