I have just replaced a Doug fir tongue $ groove entry porch with same. How soon should I "preserve it? The mill finish has been sanded but I see lots of recommendations to let it weather. Since its the entry way, this means a great deal of dirt will be introduced in the weather process over next few months, that will then require a deeper cleaning.

If we stain now ( looking at semi transparent from Cabot, but may go with Defy Extreme or TWP1500, via mail order) do we need to clean and brighten the wood as well even though it's new wood?

Please comment on the 3 products mentioned for southwest facing and plant proximity as we have some shade.