[onewhippedpuppy]

If the composite decking is solid, then yes you could use a scarf joint. Though I'm still not sure if it would be worth the trouble, and you lose the gap for the boards to expand and contract with temperature. I use the heck out of torx screws, for decking with exposed holes you can buy them with mini heads to minimize the hole size, and in colors to minimize the screw head appearance.

Mark is correct about temperature, my cedar colored composite decking gets very hot in the sun. Fortunately most of my deck is covered, my dog doesn't like to hang out in the sun on the uncovered part.

We just re-stained our railings and posts, which are cedar. I sanded them first, then used a semi-transparent stain that I think is warrantied for 5 years. The more solid the stain the longer it lasts. We had previously used a stain from Menards (don't recall the brand) and it didn't last, this time we used a Behr stain from the Home Depot and were really happy. I've also used Behr paint inside and outside on our house and been very happy with the longevity and coverage.