Bruce it depends what you want for the look if you wanted the look of various wood colors meaning no stain then on the cedar using clear it will not look the same on every board you can see that in his pictures. I like the look myself. The marine spar will give better protection than the Teak Oil its not cheap and way more effort cause it probably needs at least 3 coats or more with some 600 or higher wet dry to achieve a smooth finish in between coats.
Its not a consensus its what you like and if I had a mind to had to much wine I posted a link to a much better Spar than Helsman its a Marine Spar. I told Jon about it maybe he remembers what it was I will dig through my threads in the next couple of days and let you know what it is.
On a flip not sure about the effort what I did is use a semi stain 2 coats and I was done the color is the same on all boards. Would someone pay you less if you did that really no idea.
Here is a link to my thread showing the boards.
https://tvwbb.com/showthread.php?71432-My-Redhead-Rebuild