To answer your questions; 1.) SS 1/4" bolt & locknut, with a slight recess in the rubber floor at the bolt head locations. 2.) You would install cables before securing the top of hold down. 3.) There's a 1/4" difference in dimension that way. It was a very tight/snug fit to squeeze the hold down posts together and get the threaded rod through the hold down top. It was necessary to trim 1/4" as I mentioned before. It fits like a glove. 4.) IMHO, when I finish routing and installing the floor, this set up would pass the 6' ladder drop test. It might crack the batt. but it won't come out of the hold down. Meth tank is down the road for me, but look forward to seeing what Doc has going on.