Steff,

Testing is a very sound idea, if you really see the need. It wouldn't be all that hard. Just build several spars using different methods, and load test them. You don't need to build complete wings. This way, you can compare the alternatives according to whichever standards you want to apply ( strength, weight, ease of construction, cost, etc. ). You don't need any special equipment, and you don't need to worry about variability in the materials, as you are going to have the same variability when you build your planes. Whether it is worth it to you to do this is a matter of how badly you want to optimize your design.

I would ask one question. Are you having problems with spars failing? If not, what is driving your willingness to improve them "no matter what the effort is"? There are always other places to put some more time or effort ( practicing flying, reducing drag, ... ) , so I like to leave stuff alone when it is in less need of improvement than other issues.

If you do the testing, I'd love to see your results posted.

Good luck,

banktoturn