I have just fitted the sw motec lower crash bars. Very impressed with the quality and robustness of them

They will fit over your current cylinder protection, which imo will give you great protection.
What I like about the sw motec bars:
Black color matches perfectly with my bike's black frame.
The bars are nice and narrow, does not stick out much wider than the cylinders.
If I lie the bike down on the crashbars, no part of the cyclinder touches the ground, but as you mentioned protruding rocks might scratch the cylinders.
Last positive is the price, much cheaper than oem bars...