if you like the idea of having limited assist, here are a few concepts that could be of value:
First, try looking at this, a way of temporarily limiting the maximum assist from the throttle:viewtopic.php?f=2&t=13835
It could be set up so that the limit could be defeated, giving full power if needed. The limit could be variable, with presets.
Another is using the "Cycle Analyst" for preset and variable maximum power. It is expensive in comparison to the first option above, but, also gives a speedometer, watt hour meter (gas gauge), amp meter for current power used, and troubleshooting tools.http://www.ebikes.ca/drainbrain.shtml