I cut all my wood to 16" so I can fit three rows wide if I stack across a 48x40 pallet. My only concern was with the middle row not getting any sun or wind.... is it going to get punky in there? I plan to top cover. Anyone else stack like this? Any issues 2-3 years later? I could turn the pallet the other way and do two rows on the 40" side but that would take up more space....