Rebuilt pumps get hotter and can dump fluid out of the reservoir. I found it concerning when my pump did it but eventually I left it until it found its own 'happy' volume and stopped dripping. Normally dipsticks don't jump out but it could happen if its a loose fitting one. My guess is that if high engine revs was a problem, you would see it as more sensitive steering and aeration of the fluid. In that case, you can resize the pulley.
Also, check the numbers on yout replacement valve parts as you might have something that's not compatible and that's giving you grief. The StrangerSite website on Mustang steering has all the releveant codes.