I remember reading this and found the site:
starboardfoils.com/pages/2020-race-plus"The 115 Plus fuselage is also available as a seperate upgrade item. An extreme version of the 115 Plus fuselage, known as the 115 Plus Plus fuselage, is also available as an upgrade item. With the 115 Plus Plus, the front wing is placed even further forwards and the tail wing angle needs to be reduced even more, from -2 to -4 degrees. Therefore, the -2 degree spacer needs to be used with the new -2 degreee 255 tail wing to give the total of -4 degrees. The 115 Plus Plus fuselage is recommended for pure upwind downwind races only. Contact your nearest Starboard Foil Specialist Centre for more information and availability."
But I've been using the 115+ with +0.5 except in light wind when I use the +1. It may be worth trying the -1.5 at first? Would be interesting to try myself.