Any synthetic power steering fluid should be fine. I was able to get royal purple locally. CHF 11S, was not available close by. A forum memeber used synthetic ATF, since it is also a hydraulic fluid and when I asked him few months after, every thing was just fine.

 

So how is it driving with the rebuilt pump.
If still bad, I would go to British Parts of Utah and buy one of their new pumps, while on sale.