With your motor I'd probably go to 3:73 for maximum power leverage. Then see how they feel in the LS.
I was paying close attention to my rpm today on a typical trip to town and favorite backcountry loop and it's a fine line between 3:55's and 3:73's. I've been speculating on this too long, the 3:73's may win. 2250 rpm with my .63 6th and 26.5 tire is 75 mph, 2500 rpm is 85 mph.
The good thing about your trans is it doesn't have the low first gear........I've never understood why you'd want lower than the 2.66. Maybe really slow parades?