I am installing 5/4 mahogany tounge and groove decking on my porch, directly on pressure-treated framing. I will be blind nailing the boards with 8d stainless steel ring shank nails to the joists, which are spaced 16" o/c. Should I leave a 1/16" gap between every third board, or abut all of the boards directly to one another? Are there any other things that I need to consider?