Many thanks for the info Frank
I had only expected info on making the tires (my part of the project) so your data is a gold mine
The group I am with (a Australian country MenShed - see What is a Men's Shed - Australian Men's Shed Association for more information on Sheds in general) is intending on using cut felloes. Being in Australia we will be using the Australian woods which were historically used. The information about needing very dry wood was not something we had considered.
Many thanks
Mi