Moog Offset K7103 installation question -'65 Barracuda

I've read quite a bit here and in Tom Condran's book about installing Moog K7103 offset upper control arm bushings to increase caster. My car has been apart for over 10 years, and back then I installed the K7103 bushings in both upper arms, and set them aside. Just to recap; the front upper control arm bushings should be installed with the offset hole away from the ball joint (arrow on bushing points to ball joint) and the rears with the offset towards the ball joint (arrow on bushing points away from ball joint). On inspecting what I did back then, I have them in the correct general orientation, but the arrows are not dead straight with the "plane" of the arm itself (as stated in the Condran book), and are off several degrees. I do remember I had a hard time getting it right and actually removed one and repressed it in. I'm thinking of removing another one and repress it in hoping for better accuracy .

Here's my questions: 1) What exactly do you align the arrow to (or away) from, (the ball joint is not specific enough) to get these right the first time, say if you used a straightedge somehow? 2) How critical is the arrow angle both left to right arm and/or towards the "plane" of the arm? 3) Nothing holds the outer bearing shell to the UCA other than pressed in friction, and I am concerned about the arm holes and/or bushing shell wearing out by removing and reinstalling these bushings more than once, which may come loose in service if not tight enough. Is this a valid concern? I'm thinking that being a few degrees off may end up being a problem when all assembled and on the alignment rack. Thanks in advance for feedback. Bob