Just sell that E body bucket o'bolts and buy a real car... an A body!

Those spindles they sell are likely the taller late B - FMJ's. The taller spindle isn't going to hurt anything, been doing those conversions for a long time and never had an "overangled" ball joint yet. A buddy did the math on the angle change and it was minimal, like 3* or less.

They should use the same balljoints you currently have on the car.