Hi there, well the volumes we post are pretty much the same ones which we see on the CAD files. However of course thickness, tail and nose width play a big part in the "feel" or stability of the boards. 115L is right in the middle of our 5'6"/105L and 5'8" 125L - why don't we have a board in-between at 115L - pretty simple, because these 2 models are only an inch apart in width, so the "feel" of the boards is actually not a huge gap. Have experienced that 1:1 as my wife progressed from 6'3" all the way thru to 5'4" recently, with me having to foil all the boards back upwind along the way (personally riding 5'2 and 5'0", before on 5'4" - the newer Sky Wings can be ridden considerably smaller than 2020/21 models due to the volume placement and thicker rails in standing area.). So it depends a bit on your weight, actual gear and plans to progress - if you can foil already, then the 5'6" should be more than enough (I know you can foil already! :-)
Should this replace your StingRay etc? or you want to use it in more or less wind than wingfoiling? give me a bit more info.