Do you still have your old original radiator so you can check the� location of the shroud holes?�
I have not done the 3A yet, but when I replaced the radiator in the CJ-5 I first slid the shroud over the fan and moved it as far back over the engine as I could..I then slipped the radiator in place and fastened it, moved the shroud forward, made sure it was centered on the fan, marked the hole locations, removed it all again to drill the holes for the shroud screws.
This is the size of the screws on my 3a...
Can you see them OK?

I would file off the points of the screws before putting them in..
I'm sure you don't need to be told to be very careful drilling!
Put a stop on the drill bit so you don't slip...