You should be at full elevatorjust at touchdown. Rob Caso float his modified Telemaster around the field the other day. We put our main spar at or very close to this point for this very reason plus the fact that this is usually the thickest part of the airfoil and we can use a deep spar cross section. What some may not realize is that this also lines up the center of lift with something called the center of flexure. This is the position along the chord where a concentrated liftload causes the wing to bend but not to twist.
Designers have to be careful here, for torsional stresses have ruined many a wing.
Mother Nature figured this out a long time ago, and she placed the quill of the bird's feather at about the quarter chord. Back in WWI, most planes had two wings each with two spars and numerous struts and diagonal wires in tension - that created a strong box structure that withstood both bending and torsional loads quite nicely. Although unseen, there were horizontal diagonal wires in both upper and lower wings that completed the box structure. Monoplanes of that period had lots of wires and wing braces to control the torsion problem, but they were never as strong as the biplanes. Tony Fokker was one of the first to study the effects of torsion.