Mr Jolly I think I can help. I want to state that contest grade balsa in the 4-6 # range is what I mean for contest balsa.

1 Contest grade or as light a standard grade as you can. Beware of balsa that is too soft.

2 contest grade just again beware of soft wood.

3 The hardest you can find. I reccomend going to basswood. I don't like balsa spars.

4 Medium grade wood.

5 I would say fairly hard wood. Medium would do if the wings are sheeted.

I hope this helps. I would sheet with contest grade as well. Be careful of heavy wood in the tail feathers. My suggestion is to buy some contest grade in the sizes you need. Then buy bundle deals (I like dealing with Lone Star for wood) and select the wood you think will work the best for your particular application. Buy extra in the bundles so you have choices. You can always use the wood for later projects. It won't go to waste.

Mark Shuman

PS look for some polyurethane glues to join sheets together for sheeting. It will require you to really pin the sheets down to hold them together. But this glue is very easy to sand the joints. It will foam out between sheets. Don't worry about that, it's normal. It will sand very well. Just a suggestion.