Rustys towhook brackets: what size bolts?

I got the rustys brackets sans bolts (i know i know, but the price was amazing). so what size and how many of each bolt do i need. for bracket to framerail and bracket to hook. ASAP please. thasnk guys!

I haven't actually install my Rusty's kit, but here what I received.

Each bracket has 2x 1-3/8" washers, 1x aircraft-style nut, and 1x 3-1/2" long, 1/2-13 bolt (grade 5). The instructions say they are 4-1/2" long(??). I believe 3-1/2" is OK.

For each hook, there are 2x 1-1/8" washers, 2x aircraft-style nuts, and 2x 2-1/2" long, 1/2-13 bolt(grade 2?,no marking).