Up till now I have either flown ARTF, or 2nd hand planes where any repairs have necessitated like for like replacement. Now I want to build from plan where I need to order the wood based on what the plan shows me. Taking advice from this forum I note that there are many views on where soft, medium or hard balsa or birch or other wood should be located, but nothing definitive, is there such a guide anywhere, and do I need to ask the balsa supplier for specific types of balsa or other wood by ordering from where the wood it to be used, e.g spar, longer on, wing skin etc?