When I did them on a gen 2, i used rail blocks under the counterweights so when I used falls to lift the car it was exactly where I wanted it to reach shackles and get on/off top.

Go by Walmart, get thick sewing needles, threader, and go to fishing aisle and get 65 pound test braided fishing line.

I did one belt at a time, drill 1/16" holes across the end 10 or so, a 1/8"-1/4" in from end. Butt ends of belts together or up to maybe a 1/8" gap, now sew the ends together with the braided fishing line. Now you can use the old belt to pull through the new belt with zero worries of scarring up or damaging the sheaves.