I'm sure that someone that has done this conversion can clarify this, but doesn't the conversion kit include all the hardware you'll need? The only thing you have to re-use are your old steering arms....which you have on order.
If the conversion kit doesn't include all the hardware, I think that 2 1/2 inch long automotive grade 8 "shoulder" bolts and nuts, with "fine" (20 pitch) threads, would work to secure the steering arms.
