"And allocate an hour per arch and get someone to help. Probably the most hateful DIY job I've done on my 90!"
Eh?????? Had to do mine again a few months ago and they only took about 10-minutes each corner single handed, why the problems?
One tip I do have is to put the slightest of tapers onto the end of the pin and they slide into place much easier, aftermarket or genuine I have had the same problem with both but this makes it a breeze. I always keep a supply of the clips in the gararge, I usually manage to recover most/all of the pins but in case I can't I have some to hand to let me complete the job.