Replacement springs tend to have open, unflattened
ends, unlike the originals. These require matching new rubber wedged packers, similar to the ones sold by Ardinesh. Due to the increased height, the packing washers may be dispensed with.
If you are refitting the original springs but the original white wedged packers have disintegrated, do not throw the bits away. They are no longer available and have a unique shallow wedge angle. Just clean the bits, assemble the jigsaw and silicon them on to one of the packing washers. They then work fine.


fractured wedge packer prior to silicon repair

Shallow wedged packer on original spring

underside of packer

 

pcock111, good information on the bottom wedge.
All springs, as you found out, are not created equal. I just installed a set like you, and the top coil was not pleasant to deal with and caused problems that I will properly have to deal with at a later date.
Getting the springs into a straight coil was not going to happen and with the top coil being cocked, it didn't let the mount set correctly.
I ended up using 3 spring compressors to get it close, still not happy and turned it after getting the assembly into the car and some pressure on. I did it a couple of times and finally got a livable configuration. I'm betting it will go slightly off center in a short period of time.
So, I'm with you, the extra effort to get an original set up is the way to go.
My numbers were good on the final measurements, and the car drives better than ever, well, since I had it.
Thanks for bringing this to our attention, yes, we need to be careful with that little plastic bit.

 

Any reason not to grind the new springs to better sit?
wj

 

Would imagine they are forged flat, originally. Could affect heat treatment using DIY grinding. The set-up would be difficult to achieve flatness perpendicular to spring axis. If you have to change, safer to find wedged packer matched to new spring I feel. Dave.