Having trouble aligning the 2 bolt holes on each side from arm to axle. I suspect the axle needs to be rotated backwards a bit - makes sense since this is to correct the castor... the question is, how?

I tried jacking the front edge of the axle
pry bar

The frame is jacked up, axle supported lightly by a jack. Wheels off ground.

What next?

 

OK scratch that

I thought I read somewhere to do the frame bolt first, then axle. Doesn't work. Do axle bolts first, then the frame. Good to go!

 

Honestly when I did it it seemed fairly easy, but the guy that I got them from said he spent a day taking them off. I put my frame on jack stands and the front axle on a 5000 pound jack. Popped the bolts off and the arms fell right off. When I put the new ones on I put the front two bolts in first then the bolt on the rear of the arm. Used my feet to push the axle back in place so that rear bolt aligned and wiggled it in. Took about 2-3 from start to finish. Mine are the qt 3 degree arms.

 

Sounds about right. The whole job was pretty painless. The hard part was getting those bushings in.

Don't forget to check your springs before dropping the frame... both my springs popped out of the upper mounts. Oops