Large ball joints, small ball joints, & Aussie spindles & brakes

There have been some posts of late regarding large ball joints & small ball joints, and I guess I need some help.

The front rotors on Barry's/Bazza's '71 VG Valiant are beyond "minimum", and when we took the car back a couple weeks ago I told him they need to be replaced NOW, as I felt the car could be unsafe to drive. Problem is, new rotors (from Oz) are around $250 each, and that's a little more than he (or I can) can afford right now.

But I've been thinking about this....

I'm going back up there this weekend, and while there I was thinking of seeing how he felt about swapping-out the Aussie (Girling) front brakes (rotors, calipers, hoses, and even the spindles, if necessary) for US based parts. I haven't done my homework yet, and I don't have the Manual anymore (it went back home with the car), but now I'm wondering if I should hold-off on this idea, as I don't know what ball joints the car has.

Oh, and with regards to that: All of the new parts for the front end came from Oz. Some were in boxes, and some just in bags. Thankfully the inner and outer tie rods were in boxes, with good part numbers that crossed-over to US Dart parts (I had to source new adjusting sleeves for them), and from what I could see, the ball joints look exactly like Dart units. But I didn't measure anything...

Since I'm going back up there this weekend, what do I need to know/what should I measure or look at on these ball joints so I can start doing some research on swapping-out his brakes?

Thanks.

Jim