6 Inch lag bolts are nice, but do you worry about killing the tree? Regardless of what you use, I check the stand every time I get in (everyone should, metal or wood!). And the metal straps just add a little bit more of extra precaution in the case the nails don't hold (and those metal straps, doubled up, would hold the stands no problem for years alone). Now that I've built a wood ladder type stand on one tree, those are the way to go. They are more resistant to the tree sway, because its just one tree, they can move with the tree with out issue (from what I have seen). This "three tree" was built really for use for just a few seasons until we get to know the property better, they are easy to build and last a pretty long time.