I'll keep the center bar, that's what kept the springs straight on my 60 in my recent accident. X2 on looking the ones from MAF.I've made a couple of sets.
2 x 3/8 inch bar stock. Bored holes in a drill press so they are straight. The pin size is 18mm, I used high grade bolts. You will be changing bushings, so I think there is a bushing with a 5/8 hole that fits FJ60. 5/8 bolts are easier to find. You don't need the center "H" bar, in fact it is preferable not to have it.
It's important to keep the head of the bolt from turning. I welded on a bit of 1/4 stock to engage 1 flat of the bolt head and prevent it from rotating.
It isn't hard making shackles, but it's enough work, that buying one ready made is a decent plan. Look at the 4+ GSK bushings from MAF. These are the best available in my opinion.