ive noticed that propellers dont care about height, only that theres something above/below it for clearance, i suggest that its something like CJE's where clearance can improve when theres empty space above/below the propeller, perhaps 10 meters above and below the propeller area + x diameters, since Props i feel are more efficient than CJE's
i think this would incentivize people to use them more as an alternative to CJEs for larger crafts and make them more usable in general.