I use pine and haven’t had any problems with them as long as they are stained with an outside sealant like deck stain. After I built my first one I took it apart and tweaked it to make it more comfortable and then made a hardboard temple of each piece and jigs to line thing up when I put them together. It saves a lot of time. I originally used a plans I Found online and adjusted them to fit my needs.
Jerbear