RIS Grademarked Redwood Staining

saltymd

I am about to apply an alkyd semitransparent stain, probably Sikkens Cetol SRD 089, to a gate which is new from the mill. The client demanded Redwood that is RIS Grademarked Certified Kiln Dried, Vertical Grain, Saw-Textured, Architecural grade, Heart B.

Should I clean and prep the wood as per instructions from stain manufacturer for hardwood/mill glazed wood or should wood of this quality not have mill glaze and not need prep? They recommend a Tri-Sodium Phosphate and bleach cleaning followed by pressure wash.

What is the best way to treat the back, end grain, and joints?

Is there a specific nail hole filler and seam filler anyone recommends?