Approx 7 lbs per board
Please refer to the installation/application guide listed on the product page for your application.
I suggest reviewing the install guide listed on the product page before you purchase.
This is a tongue and groove design so the gap (or space) you're referring to is going to be tight when it fits together. Caulking the grooves is not recommend, wood can expand and contract with weather and caulking would stop that from happening and could cause damage. Please refer to the install guide listed on the product page.
Flooring is NOT an application for this product. This product is intended to be used as a cladding/siding.
transparent stain looks the best but will only last a couple of years, semi transparent lasts much longer, paint the longest.
It is smooth enough that you don't have to sand it, unless you want a fine finish. 1 side is rough.
yes, however, expensive material to be used for fencing. There are other more cost effective routes.