RE: Substitute to 1-8 balsa planking
Since nobody else jumped in......
I have been searching for easier and more efficient skinning products for some time. I had been aware of Fiberglass G-10 FR4 sheets available in either 3x4 or 4x4 panels for awhile but the cost made me shy away. But recently , after extensive searching, I found sources for the sheet at about half price from retail. I bought 11 4x4' sheets for around $325 as I recall, in various thicknesses.
I am getting ready to build a Ziroli Skyraider with foam core wings and stab that I have adjusted to be thicker as compensation for the very thin fiberglass. I will be using .010" skins and will also add a few spars but nothing too serious as the foam will keep the skin quite rigid, same as full scale stressed skin construction. The 1/6 Skyraider would have exactly 6 times (.063" aluminum) the thickness for the skins or thinner.
I have a friend who is doing his Skyraider wings and control surfaces with the G-10 over built up structure. He has a build thread on RC Scale builder, in the Ziroli section, under "Medal of honor Skyraider". You can see how he applies his skins. I also plan to do a build thread there to show the foam wing sheeting. I hate building wings so I plan to do as many of my future projects this way in the future.
I hope this will help you,