Great to see the "UK Patents Pending Preservation Mix" being accepted and used in the USA, we have been using it now for many years with great results as you have described on both wood and metal. 

If you do use linseed oil on wood, I have found it is better to use the "raw" not "boiled" linseed oil and thin it at least 50% with diesel (which also helps if there is any woodworm to control), otherwise it goes very dark and sticky as Gary described, eventually over years it will dry but then can result in cracking and peeling in sunlight. 
The other problem with using just linseed oil on wood in damp atmosphere's or winters like we have here in UK you get a fungous mold grow on the wood, when dry in the spring this just wipes off or goes with another spray of our diesel / oil mix.

Malcolm.