ORIGINAL: iron eagel

Regarding weight vs strength...
I used to build for strength and pretty much accepted the weight gain. But over the years I have found it is far better to build the airframe as strong and lightweight as possible. A lighter plane built strong will sustain less damage than a heavily built airframe. As far as wind it not the weight it's the amount of power, I fly 1 and 2 lb aircraft when most would stay home because of the wind (but these airplanes are considered way overpowered by most) and penetration is not an issue. Two of the planes in particular that are in the 2 lb range are a 43 inch span Kadet and a Easy Star both powered in the 800 watt range no problem flying them on a windy day, and both have taken some hard hits and are still flying.
A far superior method to glue fillets are gussets made of light ply (laminated pieces of balsa), and my preferred method (borrowed from timber framing) of mortising the wood to give you more glue area and a stronger joint an example of which is pictured below.