Anyone using a water pulley spacer on a magnum?

Finally got the correct water pump, and started to put on the March Performance billet pulley. Water pump is the 4 bolt style, not pressed on. I'm gonna need a pulley cover machined with CNC but that's another story.

Anyway, since there's no pulley cover I can't tighten the bolts down all the way as they bottom out in the water pump flange. But regardless I held it where it would be if it was tight and the pulley will need a spacer behind it to line up with the crankshaft pulley.

I was looking around and found lots of "universal" spacers, but none that take into account the large 1" pump shaft sticking out through the flange. All I can see are spacers with .75" holes in center. Has anyone else run into this? I'm thinking if I can't find something I'll just have to get the center machined out, but I was hoping someone else has seen this problem.

For reference, my water pump:

A1 Cardone Remanufactured Water Pumps 58-447