To add to Ray's excellent response, you might like to look at this link.
It explains that the Australian Pine wood veneer used as the outer skin of Starboard's WOOD technology
is only 0.6 mm (0.023") thick. The wood veneer is saturated on both sides with epoxy laminating resin then
applied to the board.
So, as Ray suggests, keep it out of the sun whenever possible, and do not store it outside in the varying
elements. Over time it will yellow some, but that's pretty much to be expected.
The more you keep it out of direct sunlight (when not actually sailing it) the longer the wood veneer will retian it's original "golden patina".
As to using a 3.5 m2 rig on the S-Type 115, unless you are a child/kid or lightweight woman weighing < 100 lbs. (45 kg.) and needing a small sail to keep the weight out of the rig, I agree with Ray.
The best range for the S-Type 115 would be 7.5 m2 - 5.5 m2.
Use of smaller sails due to wind conditions would also require a smaller (< 100 liters) board.
If you are an advancing beginner, the S-Type might work, but something a little wider would probably
be alot better to keep you advancing.
If you want a board that's good in chop, for it's size, the S-Type is pretty good, but it needs to be sailed fairly
powered up to get any kind of early planing performance.
Hope this helps,