When I changed my tires I also changed aspect ratios like you are considering. After all was said and done the height difference was less than 1/2" ( I measured).
I would be worried that if you went smaller you may start to have clearance issues from being to low. What size were you specifically considering? You can use this
Tire Calculator to get a rough idea of how 2 tire sizes compare. Be aware there are always slight differences between manufacturers.
btw I think the Michelin XPS RIB and the Bridgestone Duravis R250 are the 2 best choices in LR E. I think that the closed shoulder rib design is superior for trailer service. Tires like the LTX and the Transforce are better suited on trucks than trailers.