DIY axle flip kit question, Pinion angle?

[amodedude1]

So I am about to buy some leaf spring perches to to do an axle flip. I am planning on taking out all the 4wd stuff in my 79 k20 and putting in the front cross-member out of a c20 and using drop spindles and coils.

I want to keep my 8-lug all the way around so I am keeping my 14ff rear. No one makes kits for this truck and as to weather or not the c30 1ton flip kit would work or not is debatable.

On to the new question of the day:

-If I buy a new axle perch to weld on do I have to consider the pinion angle? If I just weld the new perch in keeping the surface of the new perch parallel to the old one won't that retain the correct angle? I'm a bit confused about this.

-If the pinion angle is such a concern does that mean that all the kits you could buy for these trucks have a new pinion angle already accounted for in the design of the perch?

-Lastly, would you recommend reusing the old perch by cutting it off or would buying a new perch be best?