Forgot to illustrate BMatthews' advice to use a multi-panel wing with an odd number of panels. The picture shows a 5-panel wing were the center segment is a piece of its own. The biggest bending stress of the whole wing is in the middle of this segment where no wing joiner is. The main spar is C/F reinforced, otherwise the wing is a traditional wood construction. It's a three-piece wing with two joiners quite far outboard which can be simple and lightweight. And the pieces are shorter than the fuselage while two pieces would be longer.

You see the upright V-tail and may imagine that it produces an adverse roll when used as rudder. The inverted V-tail produces proverse roll. The effect is small, though.

Just for the record: Such high-performance electric gliders have usually geared drives for reasons mentioned above. Efficiency of a good gear is about 95% because nearly all friction is rolling friction, like railway wheels on rails have. The bearings are ball or needle bearings and the toothed wheels have involute toothing. That's also why there is nearly no wear. Just an annoying whine due to straight toothing...