well bu tiny little thing, if you want to maximize the wave potential the 5'4" is a good choice.
In my case I'm buying the 5'2"cause after trying a 4'8" my taboo for going short has disappeared. I'll be using it mostly in the river but as I say, going too short on this board will be defeating the purpose of it, which is the tiny little waves that will usually keep you out of the water. I'm intending on using it for 2-3ft East Coast USA mushy fat waves, which I believe is it's perfect playground.
At the end it all comes to personal preferences and particular conditions. I've read people in this forum taking it onto head high waves...don't think I would feel comfortable dong that.
In my case, for the really small stuff I take out the SUP... ya I know, guilty as charge!!!!! but that is a real cruiser. I also have a 9'0" flexfire that I bring along the things are not certain. But usually is a matter of Spitfire and potato when I drive for waves