Ali F
Don't assume a glider is the most efficient configuration. Efficiency depends on what you are trying to achieve.
A modern high performance glider is designed to do one thing really well - to fly as far as possible for a given loss in height. To do this it has to sacrifice strength so it has a very limited payload capacity and restricted manoeuvrability.
Broader shorter wings may be a bit less aerodynamically efficient but structurally are much better so for the same weight as a glider wing it can carry a 'proper' payload and with a bigger area means it flies slower which for a power plane means less power is required.
If you look at a Skywalker in this light it is actually more 'efficient' at what it does than if it had a high performance glider configuration.
There is no simple 'one solution fits all' but just finding the best compromise to met requirements if indeed there is one.
So now, if I can pick a RTF Skywalker, with an FPV and an Autopilot (pixhawk + mission planner) will be great, and after successful flights, I can add sensors and all the measurement instruments, that will be good?