Refinish Garage Door
Correct, that type of stain is meant to look flat
I'm sure Cabot would not suggest anything over top of it, I wouldn't anyway
But give them a call...
As for the Spar....eeehhh.....
I gotta tell you it's not all that some people think it is
First off, if you don't do all six sides, moisture will creep in rather quickly
When that happens to S/V, it starts to peel and expose discolored wood
The only true fix at that point is to sand it all down and re-apply
It also needs a maintenance coat once a year
You might get more....but if you skip it and it starts to go, you get the scenario described above
For the look you want, w/o the maint., I'd recommend Sikkens Door & Window
Depending on where you are and which way the door faces, probably two coats color and a top coat of clear
You'll need to sand it down to bare wood though, so you might want to wait a year or two, when (depending) you might need a maint. coat (more Cabot) anyway, but you'll have much less to remove