I read keep it lite. The plane was designed in 1986 long before CNC, lasers, and lightened interlocking parts were used. I built one from an Ace kit and later built another from the planes however used a wing tube, substitued lite ply for the sides, hollowed out the turtle etc. I flew the original with a Quadra 52, the plans built used a G62. Flew good for it's time. Today a plane this size would sport a 80-100 cc engine.
I would replace the 1/8" ply wing spars with 1/8" balsa if it were me to save some weight.
You're just the other side of Monroeville from me, maybe one day our paths will cross, there's not many building out there. I fly at the Kittanning 268 Skykings field, how about yourself? Keystone Clippers?