linseed oilicon is all we used in Malaya. And it had a tendency to get both hot and damp there, in equal measure except at night when it was more damp than hot. This was especially so in the monsoon season which extended from the beginning of August until the end of the following June!

Just linseed oilicon on the wood and pack the metalwork under the wood with XG279 grease or the US Military equivalent and it'll see you through